WO2022167909A1

WO2022167909A1 - Antimicrobial compounds and solutions, uses thereof and methods of making the same

Info

Publication number: WO2022167909A1
Application number: PCT/IB2022/050806
Authority: WO
Inventors: Sze King James LEUNG; Heung Lin Jenny CHAN
Original assignee: Ut Innovation Limited
Priority date: 2021-02-05
Filing date: 2022-01-31
Publication date: 2022-08-11

Abstract

Provided is a compound comprising a chelated platinum ion, wherein the platinum ion is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA or NTA. In certain embodiments, the compounds or solutions provide excellent antimicrobial properties. In certain embodiments, the provided method is simple but effective in making stable chelated platinum solutions.

Description

ANTIMICROBIAL COMPOUNDS AND SOLUTIONS, USES THEREOF AND METHODS OF MAKING THE SAME FIELD OF INVENTION This application relates to antimicrobial compounds and solutions, uses thereof and methods of making the same. BACKGROUND OF INVENTION Antimicrobial agents play an important role in current personal hygiene and public health. Certain currently available antimicrobial agents may not be highly effective and may even be harmful to users. In certain examples, the antimicrobial formulations or biocides, such as nano-silver particles and nano-titanium oxide particles, often reduce the transparency of the final product. Accordingly, there is a need for novel antiseptic compounds and solutions thereof that have long-lasting, high antimicrobial effect and short action time while maintaining low toxicity to users. In addition, the production of anti-microbial plastic materials has been a challenge and often involves cumbersome manufacturing procedures. For example, the antimicrobial compositions or biocides used in plastic materials, such as nano-silver particles and nano- titanium oxide particles, often reduce the transparency of the final product. Accordingly, there is a need for improved antimicrobial compositions and methods of making and using the same. SUMMARY OF INVENTION Disclosed herein are novel compounds, compositions, salts and solutions thereof that are useful as antimicrobials, processes for preparing the compounds, compositions, salts and solutions thereof, methods of using compounds, compositions, salts and solutions thereof, and intermediates used in preparing the compounds, compositions, salts and solutions thereof . In some examples, disclosed are novel antimicrobial compositions that have wide applications. In certain embodiments, the novel antimicrobial compositions are useful in preparing aerosol sprays, or coatings for substrates, surfaces and/or ambient air. In one aspect, provided is compounds, compositions, salts and solutions of chelated platinum ion, wherein the platinum ion is chelated with a chelating agent and the chelating agent is EDTA, DTPA, GLDA, MGDA, HEDTA or NTA or an acceptable salt thereof, wherein the acceptable salt is selected from one or more of sodium, potassium, or ammonium. In some embodiments, provided is the uses of the compounds, compositions, salts and solutions thereof and methods of making the compounds, compositions, salts and solutions thereof. In another aspect, provided is compositions, salts and solutions of chelated platinum ion and a silver chelate. In some embodiments, provided is the uses of the compositions, salts and solutions of platinum chelate and silver chelate, and methods of making the same. In another aspect, disclosed herein are novel compositions that are useful for anti-septic or anti-microbial purposes, processes for preparing the compositions, methods of making antimicrobial plastic materials using the compositions, and intermediates used in preparing the compositions and the plastic materials. In some embodiments, provided is an aqueous antimicrobial composition, comprising a silver chelate and a platinum chelate. In some embodiments, provided is an aqueous antimicrobial composition, comprising: a) silver chelate about 0.0025-2%wt; b) platinum chelate about 0.0025-2%wt; and c) a stabilizing buffer about 1-5%wt. In some embodiments, provided is an aqueous antimicrobial composition, comprising: a) silver (I) tripotassium EDTA chelate chelate about 0.0025-0.01%wt; b) platinum (II) dipotassium EDTA chelate about 0.0025-0.01%wt; and c) tetraammonium ethylenediaminetetraacetate about 1-5%wt. In some embodiments, provided is an aqueous antimicrobial composition, comprising: a) silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) platinum(II) EDTA chelate (or Compound XIV) about 0.0025-0.01%wt; and c) tetraammonium ethylenediaminetetraacetate about 1-5%wt. In certain embodiments, provided is an improved antimicrobial compositions for making high light transmittance and anti-microbial plastic materials such as plastic sheets. In certain embodiments, provided is a simple approach or method in preparation of a high light transmittance and anti-microbial plastic sheets. In certain embodiments, anti-fogging agents may be incorporated into the compositions such that the anti-microbial plastic sheets become anti-fogging. In certain embodiments, the plastic sheets are biodegradable. In certain embodiments, the method may be applicable to any plastic materials in the art, for example, Acrylic, APET, BOPET, BOPP, EVA, GAG, GPPS, HDPE, HIPS, LDPE, PETG, PMMA, Polycarbonate, PP, PVC, etc. Other example embodiments are described herein. There are many advantages of the invention. In certain embodiments, the novel compounds and solutions have excellent anti-bacterial properties. In certain embodiments, the antimicrobial compounds and solutions provide good antimicrobial (including but not limited to, antibacterial, antifungal and antiviral) efficacy and short action time. For example, the antimicrobial compounds and solutions can kill bacteria, viruses and/or fungi instantly. For example, the novel compositions in certain embodiments can be used as disinfectant aerosol sprays, or coatings for any substrates or surfaces. For example, the novel compositions in certain embodiments can be added or incorporated into any materials to make novel materials with antimicrobial properties. For example, the antimicrobial compositions and the plastic sheets made from the same can kill bacteria, viruses and/or fungi instantly. In certain embodiments, the plastic sheets made from the antimicrobial compositions are bio-degradable and environmentally friendly. In certain embodiments, the antimicrobial compositions and the plastic sheets are safe for use and easy to get approval from regulatory authorities such as FDA. In certain embodiments, the plastic sheets made from the antimicrobial compositions are fog resistance, and thus are desirable in making face masks or face shield. In certain embodiments, the antiseptic plastic sheets produced are highly transparent. In certain embodiments, the antiseptic plastic sheets are prepared by simple processes, thus reducing the production cost. By way of example the novel compounds and solutions may be applied to various types of materials such as plastics and make the materials become antimicrobial. In certain embodiments, the antimicrobial compounds and solutions are transparent and useful in making compositions for plastics with high light transmittance and anti-microbial plastic materials. In certain embodiments, the antimicrobial compounds and solutions can produce outstanding amounts of negative ions in the air with a disperser. In certain embodiments, the antimicrobial compounds and solutions are safe to contact by skin, inhale, or even ingest, and are non-allergic, non-mutagenic, and non-irritant to users. In certain embodiments, the antimicrobial compounds and solutions have superior removal efficiency of Volatile Organic Compounds (VOC) such as formaldehyde, even at low concentrations or levels safe for use. Unlike titanium dioxide, the antimicrobial compounds and solutions do not require external stimulus (such as sunlight or UV light irradiation) to activate. In certain embodiments, the antimicrobial compounds and solutions provide a safe, effective and efficient way to remove air pollutants such as microorganisms, PM2.5, and VOCs such as formaldehyde and does not require evacuation during disinfection, which offers air- cleaning opportunities for settings where people with restricted mobility, e.g., at prison or elderly homes. In certain embodiments, provided is a simple approach in preparation of anti-microbial compounds and solutions, thus lowering the production costs. In certain embodiments, the provided method is simple but effective in making stable chelated platinum solutions.

BRIEF DESCRIPTION OF FIGURES Fig. 1A is a 13C{1H} NMR (100 MHz, D2O) scheme of monopotassium platinum(II) EDTA chelate (Compound (XIII) of an example embodiment. Fig. 1B is a 1H NMR (400 MHz, D2O) scheme of monopotassium platinum(II) EDTA chelate (Compound (XIII) of the example embodiment as described in Fig. 1A. Fig.1C is an ESI-MS spectrum of monopotassium platinum(II) EDTA chelate (Compound (XIII) of the example embodiment as described in Fig.1A. Fig. 2A is a 13C{1H} NMR (100 MHz, D2O) scheme of platinum(II) EDTA chelate (Compound (XIV) of another example embodiment. Fig.2B is a 1H NMR (400 MHz, D2O) scheme of platinum(II) EDTA chelate (Compound (XIV) of the example embodiment as described in Fig.2A. Fig. 2C is an ESI-MS spectrum of platinum(II) EDTA chelate (Compound (XIV) of the example embodiment as described in Fig. 2A. Fig.3 is a schematic diagram which illustrates an example antimicrobial plastic sheet of an example embodiment.

DETAILED DESCRIPTION DEFINITIONS Although the description referred to particular embodiments, the disclosure should not be construed as limited to the embodiments set forth herein. As used herein and in the claims, the terms “comprising” (or any related form such as “comprise” and “comprises”), “including” (or any related forms such as “include” or “includes”), “containing” (or any related forms such as “contain” or “contains”), means including the following elements but not excluding others. It shall be understood that for every embodiment in which the term “comprising” (or any related form such as “comprise” and “comprises”), “including” (or any related forms such as “include” or “includes”), or “containing” (or any related forms such as “contain” or “contains”) is used, this disclosure/application also includes alternate embodiments where the term “comprising”, “including,” or “containing,” is replaced with “consisting essentially of” or “consisting of”. These alternate embodiments that use “consisting of” or “consisting essentially of” are understood to be narrower embodiments of the “comprising”, “including,” or “containing,” embodiments. For example, alternate embodiments of “a solution comprising A, B, and C” would be “a solution consisting of A, B, and C” and “a solution consisting essentially of A, B, and C.” Even if the latter two embodiments are not explicitly written out, this disclosure/application includes those embodiments. Furthermore, it shall be understood that the scopes of the three embodiments listed above are different. For the sake of clarity, “comprising”, including, and “containing”, and any related forms are open-ended terms which allows for additional elements or features beyond the named essential elements, whereas “consisting of” is a closed end term that is limited to the elements recited in the claim and excludes any element, step, or ingredient not specified in the claim. “Consisting essentially of” limits the scope of a claim to the specified materials, components, or steps (“essential elements”) that do not materially affect the essential characteristic(s) of the claimed invention. In some embodiments, the essential characteristics are the basic and novel characteristic(s) of the claimed invention. For example, in some embodiments, the essential elements of a composition of the disclosure can be “X mg to Y mg” of compound A. Even if the composition includes additional agents, as long as the additional agents do not materially affect the essential characteristics of the compound, then such embodiment that “consists essentially of compound A” still includes compositions with the aforementioned additional agents. In some other embodiments, the essential components of the antimicrobial composition include at least platinum chelate. In some embodiments, the essential components of the antimicrobial composition include at least platinum(II) dipotassium EDTA chelate. In some other embodiments, the essential components of the antimicrobial composition include at least monopotassium platinum(II) EDTA chelate. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Where a range is referred in the specification, the range is understood to include each discrete point within the range. For example, 1-7 means 1, 2, 3, 4, 5, 6, and 7. As used herein, the term "about" is understood as within a range of normal tolerance in the art and not more than ±10% of a stated value. By way of example only, about 50 means from 45 to 55 including all values in between. As used herein, the phrase "about" a specific value also includes the specific value, for example, about 50 includes 50. Although the description referred to particular embodiments, the disclosure should not be construed as limited to the embodiments set forth herein. As used herein, the term “chelation” refers to a type of bonding of ions and molecules to metal ions, which involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. As used herein, the term “chelating agent” is a ligand to form chelation with a metal ion. For example, the chelating agent may be a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. As used herein, the terms “platinum chelate” or “chelated platinum” refers to a compound, or s salt thereof, comprising a platinum ion having chelation with a chelating agent. As used herein, the terms “silver chelate” or “chelated silver” refers to a compound, or a salt thereof, comprising a silver ion having chelation with a chelating agent. As used herein, the term “Volatile organic compounds” (VOC) are organic chemicals that have a high vapor pressure at room temperature. Certain VOCs such as formaldehyde are dangerous to human health or cause harm to the environment. As used herein, the term “fabric” or “textile” is a flexible material made by weaving, knitting, spreading, felting, stitching, crocheting and/or bonding from either natural and/or synthetic sources. For example, fabric can be derived from animals (e.g., wool, silk, etc.), plants (e.g., cotton, flax, jute, bamboo, etc.), minerals (e.g., asbestos, glass fiber, metal fiber/foil, etc.), and/or synthetic (e.g., nylon, polyester, acrylic, rayon, Spandex, carbon fiber, etc.). As used herein, the term “disinfectant” refers to a product used to inactivate or destroy microorganisms, such as viruses, bacteria, or fungi. NUMBERED EMBODIMENTS Set 1 1. A compound comprising a chelated platinum ion, wherein the platinum ion is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 2. The compound of embodiment 1, wherein the compound is platinum(II) diammonium EDTA chelate, platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate or Pt(II) diammonium EDTA chelate. 3. A compound of the following formula:

(Compound I). 4. A compound of the following formula:

(Compound II). 5. A compound of the following formula:

(^{Compound III).} 6. A compound of the following formula:

(Compound IV) 7. A compound of the following formula:

(Compound V). 8. A compound of the following formula:

(Compound VI) 9. A compound of the following formula:

(Compound VII) 10. A compound of the following formula:

(Compound VIII). 11. A compound of the following formula:

(^{Compound IX).} 12. A compound of the following formula:

(Compound X). 13. A compound of the following formula:

(Compound XI). 14. A compound of the following formula:

(^{Compound XII).} 15. An aqueous antimicrobial solution comprising a platinum chelate, wherein the platinum is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 16. The aqueous antimicrobial solution of embodiment 15, wherein the platinum chelate is platinum(II) diammonium EDTA chelate, platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate or Pt(II) diammonium EDTA chelate. 17. The aqueous antimicrobial solution of any one of embodiments 15-16 having a pH of about pH 6-10. 18. A method of preparing an aqueous antimicrobial solution, comprising the steps of: (i) dissolving a platinum salt slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent (e.g., ethylenediaminetetraacetic acid diapotassium salt) at a suitable mole ratio (e.g., about 18:1 - 22:1) at a temperature about 95°C for about 24 hours with stirring; (iii) mixing an alkaline with the solution; (ii) adjusting the final pH of the mixture to about pH 6-10; and (iii) making up the solution with double distilled water to a desired concentration. 19. A method of preparing an aqueous antimicrobial solution, comprising the steps of: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent (e.g., ethylenediaminetetraacetic acid diapotassium salt) at a mole ratio of about 18:1 - 22:1 at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 50%(v/v) NH₄OH with the solution; (ii) adjusting the final pH of the mixture to about pH 6-10 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; and (iii) making up the solution with double distilled water to a desired concentration. Set 2 1. A compound comprising a chelated platinum ion, wherein the platinum ion is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 2. The compound of embodiment 1, wherein the compound is platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, or platinum(II) EDTA chelate. 3. The compound of embodiment 1 having the following formula:

(Compound I). 4. The compound of embodiment 1 having the following formula:

(Compound II). 5. The compound of embodiment 1 having the following formula:

(^{Compound III).} 6. The compound of embodiment 1 having the following formula:

(Compound IV) 7. The compound of embodiment 1 having the following formula:

(^{Compound V).} 8. The compound of embodiment 1 having the following formula:

(^{Compound VI)} 9. The compound of embodiment 1 having the following formula:

(Compound VII) 10. The compound of embodiment 1 having the following formula:

(Compound VIII). 11. The compound of embodiment 1 having the following formula:

(Compound IX). 12. The compound of embodiment 1 having the following formula:

(^{Compound X).} 13. The compound of embodiment 1 having the following formula:

(^{Compound XI).} 14. The compound of embodiment 1 having the following formula:

(Compound XII). 15. The compound of embodiment 1 having the following formula:

(^{Compound XIII).} 16. The compound of embodiment 1 having the following formula:

(Compound XIV). 17. A composition comprising a compound of any one of embodiments 1 to 16, or a salt thereof. 18. An aqueous antimicrobial solution comprising a platinum chelate, wherein the platinum is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 19. The aqueous antimicrobial solution of embodiment 18, wherein the platinum chelate is platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, or platinum(II) EDTA chelate. 20. The aqueous antimicrobial solution of embodiment 18, wherein the platinum chelate is a compound of any one of embodiments 3 to 16 (Compound I to Compound XIV), or a salt thereof. 21. The aqueous antimicrobial solution of any one of embodiments 18-20 having a pH of about pH 6-10. 22. A method of preparing an aqueous antimicrobial solution, comprising the steps of: (i) dissolving a platinum salt slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent at a suitable mole ratio at a temperature about 95°C for about 24 hours with stirring; (iii) mixing an alkaline with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10; and (v) making up the solution with double distilled water to a desired concentration. 23. The method of embodiment 22, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 24. The method of embodiment 22, wherein the chelating agent is ethylenediaminetetraacetic acid dipotassium salt. 25. The method of embodiment 22, wherein the platinum salt is a sodium salt of, a potassium salt of, a nitrate salt of, a chloride salt of, or an ammonium salt of platinate. 26. The method of embodiment 22, wherein the platinum salt is a platinum (IV) nitrate, platinum(IV) chloride, tetraammineplatinum(II) nitrate, chloroplatinic acid hexahydrate, ammonium chloroplatinate, dichlorodiammineplatinum(II), potassium hexachloroplatinate (IV), potassium tetrachloroplatinate(II), tetraammineplatinum(II) chloride hydrate 27. The method of embodiment 22, wherein the suitable mole ratio is about 18:1 – 22:1. 28. The method of embodiment 22, wherein the suitable mole ratio is about 1:1. 29. The method of embodiment 22, wherein the alkaline is 25-50%(v/v) NH₄OH, KOH or NaOH. 30. The method of embodiment 22, wherein the platinum salt is potassium hexachlotoplatinate (IV). 31. A method of preparing an aqueous antimicrobial solution, comprising the steps of: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with ethylenediaminetetraacetic acid dipotassium salt at a suitable mole ratio of about 1:1at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 25%(v/v) NH₄OH with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; and (v) making up the solution with double distilled water to a desired concentration. Set 3 1. An aqueous antimicrobial composition, comprising: a) a silver chelate about 0.0025-2%wt; b) a platinum chelate about 0.0025-2%wt; and c) a stabilizing buffer about 1-5%wt. 2. The aqueous antimicrobial composition of embodiment 1, wherein the silver chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA. 3. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the platinum chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA or MGDA. 4. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the silver chelate is silver(I) tripotassium EDTA chelate, Ag(I) diammonium MGDA chelate, Ag(I) dipotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) dipotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate or Ag(I) triammonium EDTA chelate. 5. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the platinum chelate is platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate or Pt(II) diammonium EDTA chelate. 6. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the stabilizing buffer maintains pH of the composition above 8.0. 7. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein a) silver(I) tripotassium EDTA chelate about 0.0025-0.01%wt; b) platinum(II) dipotassium EDTA chelate about 0.0025-0.01%wt; and c) tetraammonium ethylenediaminetetraacetate about 1-5%wt. 8. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising a surfactant about 0.1-0.3%wt. 9. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the surfactant is Tergopren 5840 and/or BYK-300. 10. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising an adhesive about 0.5-2.0%wt. 11. The aqueous antimicrobial composition of embodiment 10, wherein the adhesive is Xiameter OFS-6040 Silane, and/or Eastman 347W. 12. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising an anti-fogging agent about 10-20%wt. 13. The aqueous antimicrobial composition of embodiment 12, wherein the anti-fogging agent is MECOSTAT-3/722 and/or PETAFD-20. 14. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising a biocide. 15. The aqueous antimicrobial composition of embodiment 14, wherein the biocide is copper EDTA chelate 0.0025-0.1%wt. 16. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the composition is made up with double distilled water. 17. An aqueous antimicrobial composition, comprising: a) silver tripotassium EDTA chelate about 0.0025-0.01%wt; b) platinum dipotassium EDTA chelate about 0.0025-0.01%wt; c) tetraammonium ethylenediaminetetraacetate about 1-5%wt; d) a surfactant (e.g., Tergopren 5840 and/or BYK-300) about 0.5-2.0%wt; e) an adhesive (e.g. Xiameter OFS-6040 Silane and/or Eastman 347W) about 0.5- 2.0%wt; and f) an antifogging agent (e.g., MECOSTAT-3/722, PETAFD-20) about 10-20%wt, wherein the composition is made up with double distilled water to 100% and wherein the composition optionally comprises copper EDTA chelate 0.0025-0.1%wt. 18. An antimicrobial plastic sheet comprising: (a) an inner plastic layer; and (b) a first outer plastic layer and a second outer plastic layer, wherein the inner plastic layer is sandwiched between the first and the second outer plastic layers each outer plastic layer is coated with the antimicrobial composition as claimed in any one of the embodiments 1-17 such that both outer surfaces of the antimicrobial plastic sheet is antimicrobial. 19. The antimicrobial plastic sheet of embodiment 18, wherein the inner plastic layer is made of a plastic raw material, and the first and the second outer plastic layers are made of a plastic raw material mixture. 20. The antimicrobial plastic sheet of embodiment 19, wherein the plastic raw material is Acrylic, APET, BOPET, BOPP, EVA, GAG, GPPS, HDPE, HIPS, LDPE, PETG, PMMA, Polycarbonate, PP and/or PVC. 21. The antimicrobial plastic sheet of embodiment 19, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%. 22. The antimicrobial plastic sheet of embodiment 20, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g.EcoPure) about 0-3%wt. 23. A method of preparing an antimicrobial plastic sheet, comprising the steps of: (i) co-extruding a plastic raw material and a plastic raw material mixture comprising the plastic raw material and additives (e.g., anti-blocking agent, silicone dioxide and biodegradable additive) together to form a plastic sheet, wherein the plastic raw material forms an inner plastic layer and the plastic raw material mixture forms two outer plastic layers such that the inner plastic layer is sandwiched between the two outer plastic layers; and (ii) coating a layer of the antimicrobial composition as claimed in any one of the embodiments 1-11 onto the outer surface of the outer plastic layer to form an antimicrobial surface, such that the plastic sheet become antibacterial. 24. The method of embodiment 23, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%. 25. The methods of any one of embodiments 22-24, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g.EcoPure) 0-3%wt. 26. The method of any one of embodiments 22-25, wherein the step (ii) further comprising the steps of: (1) dosing and weighing the first raw material mixture and the second raw material mixture; (2) mixing, melting, degassing, and de-volatilizing the first and second raw material mixtures to form melted, first polymer and second polymer; and (4) cooling and pressing the first and second polymers from a T-shaped die to form a plastic sheet. 27. The method of preparing an antimicrobial plastic sheet of embodiment 26, further comprising the step of: (5) drying the plastic sheet at about 70± 10 °C. Set 4 1. A compound comprising a chelated platinum ion, or a salt thereof, wherein the platinum ion is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 2. The compound of embodiment 1, or a salt thereof, wherein the compound or the salt thereof is selected from a group consisting of platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate), Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, and platinum(II) EDTA chelate. 3. The compound of embodiment 1, or a salt thereof, having the following formula:

(Formula I), wherein X⁺ is a cation. 4. The compound of embodiment 3, wherein the cation is a monovalent cation selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺. 5. The compound of embodiment 1, or a salt thereof, having the following formula:

(Formula II), wherein X⁺ and Y⁺ are cations, respectively. 6. The compound of embodiment 5, wherein each of the cations of X⁺ and Y⁺ is a monovalent cation selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺. 7. The compound of embodiment 5, wherein X⁺ is H⁺ or K⁺, and Y⁺ is H⁺. 8. The compound of embodiment 1, or a salt thereof, having the following formula: (Compound XV). 9. The compound of embodiment 1, or a salt thereof, having the following formula: (Compound XVI). 10. A composition comprising a compound of any one of embodiments 1 to 9, or a salt thereof. 11. An aqueous solution comprising a platinum chelate, or a salt thereof, wherein platinum is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 12. The aqueous solution of embodiment 11, wherein the platinum chelate or a salt thereof is selected from a group consisting of platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, and platinum(II) EDTA chelate. 13. The aqueous solution of embodiment 11, wherein the platinum chelate or a salt thereof is a compound of any one of embodiments 1 to 9, or a salt thereof. 14. The aqueous solution of any one of embodiments 11-13 having a pH of about pH 6- 10. 15. A method of preparing an aqueous solution, comprising the steps of: (i) dissolving a platinum salt slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent at a suitable mole ratio at a temperature about 95°C for about 24 hours with stirring; (iii) mixing an alkaline with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10; and (v) making up the solution with double distilled water to a desired concentration. 16. The method of embodiment 15, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 17. The method of embodiment 15, wherein the chelating agent is ethylenediaminetetraacetic acid dipotassium salt. 18. The method of embodiment 15, wherein the platinum salt is a sodium salt of, a potassium salt of, a nitrate salt of, a chloride salt of, or an ammonium salt of platinate. 19. The method of embodiment 15, wherein the platinum salt is a platinum (IV) nitrate, platinum(IV) chloride, tetraammineplatinum(II) nitrate, chloroplatinic acid hexahydrate, ammonium chloroplatinate, dichlorodiammineplatinum(II), potassium hexachloroplatinate (IV), potassium tetrachloroplatinate(II), tetraammineplatinum(II) chloride hydrate. 20. The method of embodiment 15, wherein the platinum salt is the compound of any one of embodiments 1 to 9, or a salt thereof. 21. The method of embodiment 15, wherein the suitable mole ratio is about 18:1 – 22:1. 22. The method of embodiment 15, wherein the suitable mole ratio is about 1:1. 23. The method of embodiment 15, wherein the alkaline is 25-50%(v/v) NH₄OH, KOH or NaOH. 24. The method of embodiment 15, wherein the platinum salt is potassium hexachlotoplatinate (IV). 25. A method of preparing an aqueous solution, comprising the steps of: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with ethylenediaminetetraacetic acid dipotassium salt at a suitable mole ratio of about 1:1at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 25%(v/v) NH₄OH with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; and (v) making up the solution with double distilled water to a desired concentration. 26. An aqueous solution prepared by the method of any one of embodiments 15-25. 27. A use of the compound of any one of embodiments 1 to 9, or a salt thereof, or the composition of embodiment 10, or the aqueous solution of any one of embodiments 11-14 as a disinfectant. 28. The use of embodiment 27, wherein the disinfectant is an aerosol spray for ambient air and/or substrate surfaces. 29. The use of embodiment 27, wherein the disinfectant is a coating for substrates. 30. The use of embodiment 29, wherein the substrates is selected from the group consisting of fabrics, plastics, metals, glass, wood, paper, concrete, ceramics, and combinations and composites thereof. 31. The use of embodiment 30, wherein the fabrics is selected from the group consisting of polyester and cotton. 32. A use of the compound of any one of embodiments 1 to 9, or a salt thereof, or a composition of embodiment 10, or the aqueous solution of any one of embodiments 11-14 and 26 for removing one or more air pollutants. 33. The use of embodiment 32, wherein the one or more air pollutant is selected from the group consisting of volatile organic compounds, microorganisms, particulates. 34. The use of embodiment 33, wherein the volatile organic compounds is formaldehyde. 35. The use of embodiment 34, wherein the particulates is Particulate Matter 2.5. 36. A composition comprising the compound of any one of embodiments 1 to 9, or a salt thereof, wherein the composition further comprises silver chelate. 37. An aqueous solution comprising a platinum chelate and a silver chelate. 38. The aqueous solution of embodiment 37, wherein the platinum chelate is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. 39. The aqueous solution of embodiment 37, wherein the platinum chelate, or a salt thereof, is selected from the group consisting of Pt(II) diammonium EDTA chelate, platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, or platinum(II) EDTA chelate. 40. The aqueous solution of embodiment 37, wherein the platinum chelate is a compound of any one of embodiments 3 to 9, or a salt thereof. 41. The aqueous solution of any one of embodiments 37-40, wherein the silver chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA. 42. The aqueous solution of any one of embodiments 37-41, wherein the silver chelate, or a salt thereof, is selected from a group consisting of silver(I) tripotassium EDTA chelate, Ag(I) diammonium MGDA chelate, Ag(I) monopotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) monopotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate, and Ag(I) triammonium EDTA chelate. 43. An aqueous antimicrobial composition, comprising: a) a silver chelate about 0.0025-2%wt; b) a platinum chelate about 0.0025-2%wt; and c) a stabilizing buffer about 1-5%wt. 44. The aqueous antimicrobial composition of embodiment 43, wherein the silver chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA. 45. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the platinum chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA. 46. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the silver chelate is selected from a group consisting of silver chelate, silver(I) tripotassium EDTA, Ag(I) diammonium MGDA chelate, Ag(I) dipotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) dipotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate and Ag(I) triammonium EDTA chelate. 47. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the platinum chelate is selected from a group consisting of platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, Pt(II) diammonium EDTA chelate, platinum(II) monopotassium EDTA chelate, or Platinum(II) EDTA. 48. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the stabilizing buffer maintains pH of the composition above 8.0. 49. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein a) Silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) Platinum(II) EDTA chelate (e.g., Compound XIV) about 0.0025-0.01%wt; and c) tetraammonium ethylenediaminetetraacetate about 1-5%wt. 50. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising a surfactant about 0.1-0.3%wt. 51. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the surfactant is Tergopren 5840 and/or BYK-300. 52. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising an adhesive about 0.5-2.0%wt. 53. The aqueous antimicrobial composition of embodiment 52, wherein the adhesive is Xiameter OFS-6040 Silane, and/or Eastman 347W. 54. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising an anti-fogging agent about 10-20%wt. 55. The aqueous antimicrobial composition of embodiment 54, wherein the anti-fogging agent is MECOSTAT-3/722 and/or PETAFD-20. 56. The aqueous antimicrobial composition of any one of the preceding embodiments, further comprising a biocide. 57. The aqueous antimicrobial composition of embodiment 56, wherein the biocide is copper EDTA chelate 0.0025-0.1%wt. 58. The aqueous antimicrobial composition of any one of the preceding embodiments, wherein the composition is made up with double distilled water. 59. An aqueous antimicrobial composition, comprising: a) Silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) Platinum(II) EDTA chelate chelate about 0.0025-0.01%wt; c) tetraammonium ethylenediaminetetraacetate about 1-5%wt; d) a surfactant (e.g., Tergopren 5840 and/or BYK-300) about 0.5-2.0%wt; e) an adhesive (e.g. Xiameter OFS-6040 Silane and/or Eastman 347W) about 0.5- 2.0%wt; and f) an antifogging agent (e.g., MECOSTAT-3/722, PETAFD-20) about 10-20%wt, wherein the composition is made up with double distilled water to 100% and wherein the composition optionally comprises copper EDTA chelate 0.0025-0.1%wt. 60. An antimicrobial plastic sheet comprising the aqueous antimicrobial composition of any one of the preceding embodiments; and optionally the at least one surface of the antimicrobial plastic sheet is treated with (e.g., coated with, sprayed with, or immersed into) the aqueous antimicrobial composition. 61. The antimicrobial plastic sheet of embodiment 60, comprising: (a) at least one plastic layer; and (b) a top antimicrobial plastic layer and/or a bottom antimicrobial plastic layer, wherein the at least one plastic layer is sandwiched between the top and the bottom antimicrobial plastic layers, the top antimicrobial plastic layer and/or the bottom antimicrobial plastic layer is/are treated with (e.g., coated with, sprayed with or immersed into) the antimicrobial composition as claimed in any one of the preceding embodiments such that at least one outer surface of the antimicrobial plastic sheet is antimicrobial. 62. The antimicrobial plastic sheet of embodiment 61, wherein the at least one plastic layer is made of a plastic raw material, a pre-consumer content material and/or a post- consumer content material, and the top antimicrobial plastic layer and/or the bottom antimicrobial plastic layer is/are made of a plastic raw material mixture, a pre-consumer content material and/or a post-consumer content material. 63. The antimicrobial plastic sheet of embodiment 62, wherein the plastic raw material is Acrylic, APET, BOPET, BOPP, EVA, GAG, GPPS, HDPE, HIPS, LDPE, PETG, PMMA, Polycarbonate, PP and/or PVC. 64. The antimicrobial plastic sheet of embodiment 62, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%. 65. The antimicrobial plastic sheet of embodiment 62, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g. EcoPure) about 0-3%wt. 66. A method of preparing an antimicrobial plastic sheet, comprising the steps of: (i) co-extruding a plastic raw material and a plastic raw material mixture comprising the plastic raw material and additives (e.g., anti-blocking agent, silicone dioxide and biodegradable additive) together to form a plastic sheet, wherein the plastic raw material forms an inner plastic layer and the plastic raw material mixture forms two outer plastic layers such that the inner plastic layer is sandwiched between the two outer plastic layers; and (ii) coating a layer of the antimicrobial composition as claimed in any one of the embodiments 1-11 onto the outer surface of the outer plastic layer to form an antimicrobial surface, such that the plastic sheet become antibacterial. 67. The method of embodiment 66, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%. 68. The methods of any one of embodiments 66-67, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g.EcoPure) 0-3%wt. 69. The method of any one of embodiments 66-68, wherein the step (ii) further comprising the steps of: (1) dosing and weighing the first raw material mixture and the second raw material mixture; (2) mixing, melting, degassing, and de-volatilizing the first and second raw material mixtures to form melted, first polymer and second polymer; and (3) cooling and pressing the first and second polymers from a T-shaped die to form a plastic sheet. 70. The method of preparing an antimicrobial plastic sheet of any one of embodiments 66-69, further comprising the step of: (4) drying the plastic sheet at about 70± 10 °C. EXAMPLES Provided herein are examples that describe in more detail certain embodiments of the present disclosure. The examples provided herein are merely for illustrative purposes and are not meant to limit the scope of the invention in any way. All references given below and elsewhere in the present application are hereby included by reference. The present disclosure relates to a platinum(II) chelate compound, solution of the platinum(II) chelate compound, and methods of making the same. In certain embodiments, provided is a platinum(II) dipotassium EDTA chelate compound, a solution of the platinum(II) dipotassium EDTA chelate compound and a process of preparing a platinum(II) dipotassium EDTA chelate solution. In certain embodiments, provided is a monopotassium platinum(II) EDTA chelate compound, a solution of the monopotassium platinum(II) EDTA chelate compound and a process of preparing a monopotassium platinum(II) EDTA chelate solution. In certain embodiments, provided is a platinum(II) EDTA chelate compound, a solution of the platinum(II) EDTA chelate and a process of preparing a platinum(II) EDTA chelate solution. In certain embodiments, provided is a compound, or a salt thereof, having a formula of

(Formula I), wherein X⁺ is a cation. In a further embodiment, the cation is a monovalent cation. In a further embodiment, the cation is selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺. In certain embodiments, provided is a compound, or a salt thereof, having a

formula of (Formula II), wherein X⁺ and Y⁺

are a cation, respectively. In a further embodiment, the cation is a monovalent cation. In a further embodiment, the cation is selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺. In a further embodiment, X⁺ is K ⁺ and Y⁺ is H ⁺. In a further embodiment, X⁺ is H⁺ and Y⁺ is H⁺. In certain embodiments, provided is a compound selected from Table 1 (Compound I – Compound XVI), a solution thereof and a process of preparing solution thereof. In certain embodiments, provided is a compound having a formula of (compound XIII), a solution thereof and a

process of preparing a solution thereof. In certain embodiments, provided is a compound

having a formula of

(compound XIV), a solution thereof and a process of preparing a solution thereof. In certain embodiments, provided is a compound having a formula of

(compound XV), a solution thereof and a process of preparing a solution thereof. In certain embodiments, provided is a compound having a formula of

(compound XVI), a solution thereof and a process of preparing a solution thereof. By way of example, the platinum chelate solution is useful in preparing an antimicrobial composition for, but not limited to, plastic coatings. Nobel metal such as platinum is extremely stable. It requires high activation energy to break up the covalent bonds between platinum atoms. On the contrary, some of the platinum salts are readily soluble in water, which can be used as a starting material for the preparation of Platinum(II) chelates. Water soluble platinum salt such as, but not limited to, platinum(IV) nitrate, platinum(IV) chloride, tetraammineplatinum(II) nitrate, chloroplatinic acid hexahydrate, ammonium chloroplatinate, dichlorodiammineplatinum(II), potassium hexachloroplatinate(IV), potassium tetrachloroplatinate(II), tetraammineplatinum(II) chloride hydrate can be used as a starting material for the preparation of platinum(II) chelates. The procedure is based on the chemical reaction between a chelating agent and a platinum salt. The choice of a chelating agent can be a sodium salt of, a potassium salt of, or an ammonium salt of chelating agents EDTA, DTPA, GLDA, MGDA, HEDTA or NTA. EXAMPLE 1 COMPOUND EMBODIMENTS In certain examples, platinum chelate compounds are selected from one or more of the compounds described in Table 1.

Table 1. Example compound embodiments of antimicrobial compounds (platinum chelates). EXAMPLE 2 PREPARATION OF PLATINUM CHELATE SOLUTION General procedures In certain example examples, platinum chelate solutions are prepared as an aqueous antimicrobial solution, with the following steps: (i) dissolving platinum salt slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent at a suitable mole ratio at a temperature about 95°C for about 24 hours with stirring.; (iii) mixing alkaline with the solution; (ii) adjusting the final pH of the mixture to about pH 6-10; and (iii) making up the solution with double distilled water to a desired concentration. In certain examples, the suitable mole ratio of the solution to the chelating agent is 18:1 – 22:1. In certain examples, the suitable mole ratio of the solution to the chelating agent is about 1:1. In certain examples, the platinum salt is a water soluble platinum salt. As an example, the platinum salt may be a sodium salt of, a potassium salt of, or an ammonium salt of hexachloroplatinate or tetrachloroplatinate. As an example, the platinum salt may be one or more of platinum(IV) nitrate, platinum(IV) chloride, tetraammineplatinum(II) nitrate, chloroplatinic acid hexahydrate, ammonium chloroplatinate, dichlorodiammineplatinum(II), potassium hexachloroplatinate(IV), potassium tetrachloroplatinate(II), tetraammineplatinum(II) chloride hydrate. In certain examples, the chelating agent may be a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA. In certain examples, the alkaline may be ammonium hydroxide (NH₄OH), potassium hydroxide (KOH), or sodium hydroxide (NaOH). In certain examples, the final solution is a clear aqueous solution. In other examples, the final solution is a slightly pale yellowish, clear aqueous solution. In certain examples, the final solution may be stored at room temperature until use. The final solution may be diluted to lower concentrations as working solutions for use. The concentrations may be adjusted according to the practical need. As an example, the working solution is about 50,000ppm 40,000ppm, 30,000ppm, 20,000ppm, 10,000ppm, 9,000ppm, 8,000ppm, 7,000ppm, 6,000ppm, 5,000ppm 4,000ppm, 3,000ppm, 2,000ppm, 1,000ppm, 900ppm, 800ppm, 700ppm, 600ppm, 500ppm, 400ppm, 300ppm, 200ppm, 100ppm, 50ppm, 25ppm, 10ppm, 5ppm, 4ppm, 3ppm, 2ppm or 1ppm. As an example, the working solution is higher than about 5ppm. In certain examples, the working solution is about 5ppm. In certain examples, the working solution is about 5-100ppm. PREPARATION OF PLATINUM CHELATE SOLUTION EXAMPLE 3 In this example, platinum(II) dipotassium EDTA chelate (Compound (I) was used as an example compound to show an example antimicrobial solution is prepared as follows: 500 grams of Potassium hexachloroplatinate (IV) (CAS 16921-30-5, Sigma Aldrich) is slowly added to a reactor containing 10L about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to give a bright yellow aqueous solution. A chelating agent, ethylenediaminetetraacetic acid dipotassium salt (CAS 25102-12-9), was added to the solution at a mole ratio of about 18:1 - 22:1. The temperature of the reactor was maintained at about 95°C for about 24 hours and the reaction mass was stirred throughout. The solution then has a color change from bright yellow to faint yellow, and subsequently to colourless after 2.5L of 25%(v/v) NH₄OH was added. The final pH of the solution was adjusted to pH 6-10 with potassium hydroxide or ammonium hydroxide, and make up to a total volume of 50L with double distilled water to achieve a platinum concentration of 4014mg/L. The final solution may be stored at room temperature until use. The structure of platinum(II) dipotassium EDTA chelate is shown in Table 1. Other compounds (Compound II – Compound XII) were prepared generally using a similar method as described above and may be adjusted based on knowledge in the art. EXAMPLE 4 In this example, monopotassium platinum(II) EDTA chelate (Compound XIII/ Compound XV) was used as another example compound to show another example antimicrobial solution may be prepared as follows: 500 grams of potassium hexachlotoplatinate (IV) (CAS 16921-30-5, Sigma Aldrich) is slowly added to a reactor containing 10L about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to give a bright yellow aqueous solution. A chelating agent, ethylenediaminetetraacetic acid dipotassium salt (CAS 25102-12-9), was added to the solution at a mole ratio of about 1:1. The temperature of the reactor was maintained at about 95°C for about 24 hours and the reaction mass was stirred throughout. After the solution was cooled to room temperature, 2.5L of 25%(v/v) NH₄OH was added. The solution has a color change from bright yellow to faint yellow, and subsequently to colourless. The final pH of the solution was adjusted to pH 6-10 with potassium hydroxide or ammonium hydroxide, and make up to a total volume of 50L with double distilled water to achieve a platinum concentration of 4,014mg/L. The final solution may be stored at room temperature until use. The structure of monopotassium platinum (II) EDTA chelate is shown in Table 1. NMR data: 1H NMR (400 MHz, D2O): δ 4.23 (q, J = 16 Hz, 8H), 3.62 (s, 4H). 13C{1H} NMR (100 MHz, D2O): δ 173.9, 62.1, 59.0; MS data (ESI-MS): calculated for [Pt(II)- C₁₀H₁₂N₂O₈ ^4--K⁺]- 522.39, found 521.86. NMR schemes and MS spectrum results are shown in Figs. 1A-1B and 1C, respectively. For clarity sake, Compound XIII and Compound XV are substantially the same compound except Compound XIII overall carries an overall negative charge. Compound XIII is a conjugate base of Compound XV. The formation of these compounds depends on the pH that the compound is in. EXAMPLE 5 In this example, platinum (II) EDTA chelate (Compound XIV/ Compound XVI) was used as another example compound to show another example antimicrobial solution may be prepared as follows: 500 grams of potassium hexachlotoplatinate (IV) (CAS 16921-30-5, Sigma Aldrich) was slowly added to a reactor containing 10L about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical was completely dissolved to give a bright yellow aqueous solution. A chelating agent, ethylenediaminetetraacetic acid diammonium salt monohydrate (CAS 304675-80-7), was added to the solution at a mole ratio of about 1:1. The temperature of the reactor was maintained at about 95°C for about 24 hours and the reaction mass was stirred throughout. After the solution was cooled to room temperature, 2.5L of 25%(v/v) NH₄OH was added. The solution has a color change from bright yellow to faint yellow, and subsequently to colourless. The final pH of the solution was adjusted to pH 6-10 with ammonium hydroxide, and make up to a total volume of 50L with double distilled water to achieve a platinum concentration of 4014mg/L. The final solution may be stored at room temperature until use. The structure of platinum (II) EDTA chelate is shown in Table 1. NMR data: 1H NMR (400 MHz, D2O): δ 4.13 (q, J = 16 Hz, 8H), 3.54 (s, 4H). 13C{1H} NMR (100 MHz, D2O): δ 173.8, 61.9, 58.8; MS (ESI-MS): calculated for [Pt(II)- C₁₀H₁₂N₂O₈ ^4--H⁺]- 484.30, found 483.98. NMR schemes and MS spectrum results are shown in Figs. 2A-3B and 2C, respectively. For clarity sake, Compound XIV and Compound XVI are substantially the same compound except Compound XIV overall carries an overall negative charge. Compound XIV is a conjugate base of Compound XVI. The formation of these compounds depends on the pH that the compound is in. PERFORMANCE OF PLATINUM CHELATE SOLUTIONS In the following Examples 6-17, various tests were performed with monopotassium platinum (II) EDTA chelate (Compound (XIII) solution as an example platinum chelate solution. The platinum chelate solution was prepared as described in Example 4. The platinum chelate solution was diluted with double distilled water to a working solution before being tested. In the following examples, the working solution of the platinum chelate solution has a concentration of about 5ppm, unless otherwise specified. In certain examples, the working solution of the platinum chelate solution may also be called “a sample solution” or a “sample”. EXAMPLE 6 NEGATIVE ION COUNT The sample solution (Compound (XIII) at about 4ppm was prepared and was tested for negative ion count with a commercially available dispenser with reference to QB/T 4982- 2016. Detailed procedures are as follows. The sample solution was installed into a dispenser or atomizer (Magic Wand Humidifier, model SY-2115, Shenzhen Soyoung Technology development Co., Ltd) which was placed into a metal testing chamber with dimensions 630mm x 630mm x 800mm, with ventilation 0.25 to 0.35m/s air speed. The sample solution was atomized into the testing chamber. An AES Air Ion Counter with data logger, with which negative ion mode was set, was placed 300mm apart from the atomizer. The probe of ion counter was directly headed to testing solution stream. Sample solution stream was released for at least 10 minutes until stabilized ion count readings were obtained. The ion counts of sample solution stream was measured every one minutes for five times. The ion count results were recorded and summarized in Table 2.

Table 2. Summarized negative ion count results of the platinum chelate solution. The results show that the example chelate platinum solution produces high amounts of negative ions when atomized in the air with a dispenser. High amounts of negative ions is advantageous at least in that negative ions can purify the air by removing particulates (such as Particulate Matter 2.5 (PM2.5)), microbes, and odors from the air. EXAMPLE 7 ACUTE INHALATION TOXICITY Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test method: OECD 403 Acute inhalation toxicity Test environment: SPF animals house, certificate No. SYXK 2018-0086, Guangdong. Room temperature 22±1 °C, Relative humidity 60±5%. Experimental animals and feed: 6 Healthy SPF Kunming mice (3 females and 3 males) were selected, weighing 18.0~ 20.0 g. Animals and feed were supplied by Guangdong Medical Laboratory Animal Center. Experiment Animal Production License No.SCXK 2018-0002, Guangdong. Animal certificate No.44007200078835. Preparation of Sample: Took the sample solution directly as test substances. Exposure concentrations of Sample: A limit test exposure concentrations was 5000 mg/m³ for 4 hours. Test procedures: (1) Exposure equipment: A dynamic inhalation equipment was used, type HOPE-MED 8050. The duration of exposure was 4 hours after equilibration of the inhalation chamber. (2) Exposure condition: The inhalation chamber volume: 0.3 m³, airflow rates: 3.6 m³/h, totalled 14.7 m³. The temperature: 22±1 °C, the relative humidity: 55~85%, oxygen concentrations: 20±0.5%.The test substance relative density: 0.991. Fasted during exposure, water also was withheld. After exposure, ordinary diet. (3) Observation: The test observation were lasted for 14 days. Recorded signs of toxicity in animals, individual animal was weighed once on D0 (before dosing), D1, D3 and D7. At the end of the test animals were weighed and then humanely killed, record necropsy findings. Test results: After exposure for 14 days, no obvious toxic signs or death were observed with the mice. No obvious changes were observed in gross necropsy. The 4 hour LC50 was more than 5000 mg/m³. Animals body weight changes and response data and dose level were summarized in Table 3. y

Table 3. After exposure, tabulation of body weight changes, response data and dose level for test animals Results show that the acute inhalation toxicity at 4hours LC₅₀ of the example platinum chelate solution in mouse was more than 5000 mg/m³. According to the Globally Harmonized System (GHS) system for classification of acute inhalation toxicity, the example platinum chelate solution is classified in GHS Class 5, indicating that it has relatively low acute toxicity. EXAMPLE 8 SKIN SENSITISATION TEST Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test Method: OECD 406-1992 Test environment: Animal room of conventional condition. Certificate No. SYXK 2019- 0033 Shanghai, room temperature 20-22°C, relative humidity 45-65% The experimental animals: Guinea pigs, female, 300-500g, supplied by Shanghai KeShuo Experiment Animal Co., LTD, Certificate No. SCXK(Hu)2012-0026). The animal feed were supplied by Jiangsu Xietong Medical bio-engineering Co. LTD. License No: Su Feed Approval(2014) 01008. Test procedures: In preparation stage, the fur on all treatment sites of the guinea pigs were closely clipped or shaved to all steps in the following test procedures. At induction phase, 0.2ml of the test sample by topical application was administered to the clipper left upper back region of each animal using appropriate patches. The restrainer and occlusive dressings and patches were removed after 6 hours. This procedure was repeated for three weeks. The control animals were treated similarly, using normal saline alone. At challenge phase, fourteen days after the last induction application, all test and control animals with 0.2ml of the test sample were challenged. The test sample by a single topical application was administered to a right clipped untested area of each animal using appropriate patches. The restrainer and occlusive dressings and patches were removed after 6 hours. Observation of animals: The appearances of the challenged skin sites of the test and control animals were observed at 24 hours and 48 hours after removal of the dressings. The skin reactions for erythema and oedema were described and graded according to the Magnusson and Kligman grading (Table 4) for each challenge site and at each time interval.

Table 4. Grading scale for patch test reaction In the Magnusson and Kligman grading, the testing results of the patch test reaction were scored at 4 levels according to the patch test reaction, namely, 0 score for no visible change, 1 score for discrete or patchy erythema, 2 score for moderate and confluent erythema, 3 score for intense erythema and swelling. Result(s):

Table 5. Delayed hypersensitivity test results The patch test was conducted for delayed hypersensitivity tests with normal saline and the test article (with sample solution) individually at 24h and 48h time intervals, respectively. It was found that the sensitization rates at 24 or 48 hours of the test article (with the example platinum chelate solution) were 0% in the guinea pigs. Under the conditions of the study, the example platinum chelate solution showed no evidence of causing delayed dermal contact sensitization. EXAMPLE 9 BACTERIAL REVERSE MUTATION TEST Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test method: OECD 471 Bacterial Reverse Mutation test Materials and Methods Test strains: the histidine-deficient TA97a, TA98, TA100, TA102 and TA1535 strains of Salmonella typhimurium were purchased from MOLTOX Corporation of the United States. Before the test, all five strains were identified by laboratory, and the biological characteristics of the strains met the test requirements. Metabolic activation: the rat liver homogenate supernatant (S9) induced by PCBs was purchased from Jiangsu CHI SCIENTIFIC Biotechnology Co., Ltd. (Lot. No.20FS068C). Positive control: 1. Sodium azide (NaN3) was purchased from Chengdu XIYA Chemical Co., Ltd. (Lot: S7470), and was prepared with sterile water at a use concentration of 15 µg/ml, and the final concentration was 1.5 µg/plate. 2. 2-Aminofluorene (2-AF) was purchased from sigma-aldrich (Lot: S90850V) of the United States. It was formulated with dimethyl sulfoxide (DMSO) at a use concentration of 100 µg/ml, and the final concentration was 10.0 µg/plate. 3. Sodium p(dimethylamino)benzenediazo sulfonate was purchased from ChemService Corporation of the United States (Lot: 3042900), and was prepared with sterile water at a concentration of 500 µg/ml, with a final concentration of 50 µg/plate. 4. Mitomycin C was purchased from MCE Corporation of the United States (Lot: 25192), and was prepared with sterile water at a use concentration of 40 µg/ml, with a final concentration of 4.0 µg/plate. 5. 1,8-dihydroxyanthraquinone was purchased from Aladdin Reagents (Shanghai) Co., Ltd. (Lot: 11523115), formulated with DMSO to a use concentration of 500 µg/ml, and a final concentration of 50 µg/plate. 6. 2-Aminoanthracene (2-AA) was purchased from TCI Corporation of Japan (Lot: 7GCCl-po), and was prepared with DMSO at a use concentration of 30 µg/ml, with a final concentration of 3.0 µg/plate. Test substance: The sample solution was made into a series of relevant poisoning liquids with sterilized water. Dose design: the test dose was designed according to the solubility of the test substance and bacterial toxicity. Test methods: 1. Grouping: Through the pre-test, the minimum inhibitory concentration of the test substance on TA100 was 100 µL/plate without the addition of S9.100 µL/plate was taken as the highest dose, the following set four doses of 50 µ/L plate, 25 µL/plate, 12.5 µL/plate, 6.25 µL/plate, and three parallel plates were taken for each dose. At the same time, a blank control group, a solvent control group, a positive control group and a sterile control group were set. 2. Plate incorporation method: The test was conducted with and without S9.2.0ml of top agar medium were divided into test tubes and incubated in a 45°C water bath, then 0.1ml of test strain enrichment solution, 0.1ml of test substance solution and 0.5ml of phosphate buffer or 0.5ml S9 Liquid (when metabolic activation was required) were added to each tube, well mixed. The mixture was quickly poured into the bottom medium plate, and the plate was rotated to make it evenly distributed. After being placed horizontally to be condensed and solidified, it was placed in a 37°C biochemical incubator for 48 hours, and the number of returning colonies per dish was recorded. 3. Judgment of results: The number of returning colonies of the test substances TA97a, TA98, TA100, TA102 was two times or more than the number of returning colonies of the solvent control group, and if the number of returning colonies that test substance in TA1535 three times or more than solvent control group, and one of the following conditions occurred: (1) a dose-response relationship; (2) under any dose condition, a positive reaction and repeatable, the test substance was judged to be positive for mutagenicity. After the test substance was determined by the above five test strains, as long as there was one test strain, whether it was positive under the condition of adding S9 or not, the bacterial reverse mutation test of the test substance can be reported to be mutagenic. If the test substance was tested by 5 test strains, whether it was negative with or without S9, it can be reported that the test substance was negative for mutagenesis. Test results: Test results are summarized in Table 6, which shows that the number of returning colonies in the blank control group, solvent control group, and positive control group was within the normal range, and the experimental system met the requirements. Without S9, the TA100 strain showed bacteriostatic conditions at a dose of 100 µL/plate. The number of retrograde colonies of TA97a, TA98, TA100, TA102 in 50 µL/plate, 25 µL/plate, 12.5 µL/plate, 6.25 µL/plate with and without S9 did not reach 2 times, and the number of TA1535 reverse colonies did not reach three times that of the solvent control group. Strains Dose/Control -S9 +S9 Mean±SD Mean±SD B^{lank control} _{114±4 125±12} Solvent control 116±6 118±6 100µL/plate 128±5 128±9 50µL/plate 121±5 142±8 TA97a 2^5µL/plate _{120±3 121±7} 12.5µL/plate 120±3 110±3 6^.25µL/plate _{119±5 128±3} Positive control 1672±22 791±30 Blank control _{37±1 34±1} Solvent control 34±2 34±2

Table 6. The number of colonies changed by AMES test strains (Mean±SD). Note: lnh means bacteriostasis. Without S9 (-S9): For TA97a and TA98 sodium p(dimethylamino)benzenediazo sulfonate was used as a positive control; for TA100 and TA1535 NaN3 was used as a positive control; for TA102 mitomycin C was used as a positive control. Under the condition of adding S9 (+S9): For TA97a, TA98 and TA1002- AF was used as a positive control; for TA102, 1,8-dihydroxyanthraquinone was used as a positive control; and for TA1535, 2-AA was used as a positive control. Results show that, under the conditions of this test, the example platinum chelate solution shows no mutagenicity with and without the addition of a metabolic activation system. EXAMPLE 10 ACUTE DERMAL IRRITATION/CORROSION TEST Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test method: OECD 404:2015 OECD Guideline for testing of chemicals Acute Dermal Irritation/corrosion Test environment: Rabbit room of conventional condition. The number of the using of laboratory animals was No. SYXK（Yue）2018-0086. The temperature was between 21°Cand 23°Cand the relative humidity was between 50% and 60%. Test animals: New Zealand white albino rabbits, weighing between 2.1kg and 2.3kg at the start of the test, were used. They were supplied by Guangdong Medical Laboratory Animal Center (Sanshui Base). The number of the production of laboratory animals was No. SCXK (Yue) 2019-0035. The animal certificate number was No.44411600006437. No. of animals for test and sex: 3; Female (F): Male (M) ratio = 2:1. Preparation of sample: the undiluted sample solution was used as test substance. Observation period: 1, 24, 48 and 72 hours after residual test substance removal. Test procedures: (1) Initial test: 1 healthy young adult New Zealand white albino rabbit was selected. Approximately 24 hours before the test, fur was removed by closely clipping the dorsal area of the trunk of the animal with care to avoid abrading the skin. Two dorsal areas (each area approximately 6cm²) were prepared and 0.5ml test substance was applied to the left side with a gauze patch respectively. The patch was loosely held in place with non-irritating tape and suitable semi-occlusive dressing. A gauze patch was applied to the other site as a control. After 4 hours of exposure, the patches were removed and the test area were wiped clean using warm water. (2) Examination: Signs of erythema and edema were examined at 1, 24, 48 and 72 hours after residual test substance removal. The signs of erythema and edema were graded as scores with the following criteria. Signs of erythema and edema were examined on the basis of the method described at 1, 24, 48 and 72 hours after residual test substance removal, the responses at each observation period were scored and recorded.

Table 7. OECD 404:2015 Grading of skin reactions of erythema and edema (oedema). Histopathological examination may be carried out to clarify equivocal responses. Results: The results showed that there was no corrosive or severe irritant effect. In the confirmatory test, two additional animals were used to finish the test, performed the same as (1). Signs of erythema and edema were examined on the basis of method at 1, 24, 48 and 72 hours after residual test substance removal, the responses at each observation period were scored and recorded and summarized in Tables 8A and 8B.

Table 8A. Erythema and edema scores of the test substance at 1 hour and 24 hours.

Table 8B. Erythema and edema scores of the test substance at 48 hours and 72 hours. The test results show that no acute dermal irritation was found at any observation period with the example platinum chelate solution. EXAMPLE 11 ACUTE ORAL TOXICITY Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test method: OECD 423: 2002 OECD Guideline for testing of chemicals Acute oral toxicity – Acute Toxic Class Method Test environment: SPF animals house, certificate No. SYXK 2018-0086, Guangdong. Room temperature 22±1°C, Relative humidity 60±5%. Experimental animals and feed: 6 Healthy SPF Kunming females mice were selected, weighing 18.0~ 20.0 g. Animals and feed were supplied by Guangdong Medical Experiment Animal Center. Experiment Animal Production License No. SCXK 2018-0002, Guangdong. Animal certificate No.44007200073616. Preparation of sample: 10.0g of sample solution was taken and ultrapure water was added up to 100 ml. The solution was stirred uniformly as the test solution. Test procedures: (1) Dose: The preliminary test dose was 2000 mg/kg·bw that the test sample. No obvious toxic signs and death were observed. A limit test was used, with a dose design of 2000 mg/kg·bw. (2) Administration of Doses: The test substance was administered in a single dose by gavage using a stomach tube, 0.2ml/10g·bw. Fasted for 4 hours prior to dosing, water was available any time. After the substance had been administered, fasted for 1 hour, and ordinary diet. (3) Observation: Experimental observation lasted for 14 days. Signs of toxicity and death of animals and weight were recorded at day 0, day 7 and day 14. Results: (1) After dosing, animals body weight changes and toxic signs were summarized in Table 9A.

Table 9A. After dosing, tabulation of body weight changes and toxic signs for animals (2) Through the limit test, no obvious toxic signs and death were found. Therefore, the LD50 exceeds 2000mg/kg·bw. The results were summarized in Table 9B.

Table 9B. The results of acute oral toxicity test of example sample solution. The results show that the acute oral toxicity LD₅₀ of the example platinum chelate solution in mouse was greater than 2,000 mg/kg·bw, and thus was classified as GHS Category 5. EXAMPLE 12 PERFORMANCE TEST FOR AIRBORNE BACTERIA REMOVAL Sample solution: The chelate sample solution (Compound (XIII) at about 12ppm was prepared. Test Method The test method was in reference to Technical Standard for Disinfection – 2002 Ministry of Health of the People’s Republic of China. 1. Suspension of test bacteria E. coli was incubated and prepared, by filtering with sterile absorbent cotton and diluting with nutrient broth medium, to the required concentration (10mL, 10⁵ to 10⁶ bacterial count/mL). 2. The bacteria suspension was sprayed using a cold atomizer into a 1m³ test chamber that was controlled under the condition with temperature (20°C-25°C) and humidity (50%- 70%), and stirred for 15 minutes to steady period. 3. Sterilization Robot was turned on to spray the sample solution into the chamber. The sample solution was vaporised through Time Medical Intelligent Sterilization Robot nozzles into the test chamber. 4. Bacterial samples for performance tests were collected by liquid impingement sampler from the chamber after sterilization on 5 minutes, 15 minutes, 30 minutes and 90 minutes respectively, then impingenated medium solution was prepared and cultured in an incubator under 37°C for 48 hours, and observe the final results. 5. Control sample was prepared as the above procedures without spraying sample disinfectant; the bacterial sample was collected 30 minutes after steady period. 6. The results were recorded and removal efficiency was calculated as the following:

Results:

Table 10. Bacterial counts (before and after spraying) and % removal efficiencies of control and sample solution at different time intervals. Results show that outstanding airborne bacterial removal efficiency (98.4%) to E. coli can be achieved by spraying the example platinum chelate solution even only after 5 minutes. After spraying for 15 minutes, airborne bacterial removal efficiency reaches higher than 99% and after spraying for 90 minutes, the airborne bacterial removal efficiency reaches 99.9% (Table 10). In summary, the example platinum chelate solution achieves outstanding airborne bacterial removal efficiency within a short period of time. EXAMPLE 13 ANTIMICROBIAL EFFECTIVENESS Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. Test Method: The antimicrobial tests were performed with sample solution according to Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill Procedure (ASTM E2315- 2016). The contact time for Aspergillus niger (ATCC 16404), Candida albicans (ATCC 10231), Escherichia coli (ATCC 8739), Klebsiella pneumonia (ATCC 33495), Staphylococcus aureus subsp. Aureus Rosenbach (Methicillin – resistant strain) MRSA (ATCC 43300), Streptococcus pneumoniae (ATCC 33400) is 15 minutes, and the contact time for Legionella pneumophila (ATCC 33152) is 10 minutes. The microbial reduction rate is calculated as follows:

Test results: The contact time, microbial counts in colony forming unit per mililiter (CFU/ml) controls and samples and the microbial reduction rates of various microbial strains are summarized in Tables 11A-11D.

Table 11A. The contact time, microbial counts in colony forming unit per mililiter (CFU/ml) controls and samples and the microbial reduction rates of Aspergillus niger (ATCC 16404) and Candida albicans (ATCC 10231).

Table 11B. The contact time, microbial counts in colony forming unit per mililiter (CFU/ml) controls and samples and the microbial reduction rates of Escherichia coli (ATCC 8739) and Klebsiella pneumonia (ATCC 33495).

Table 11C. The contact time, microbial counts in colony forming unit per mililiter (CFU/ml) controls and samples and the microbial reduction rates of Staphylococcus aureus subsp. Aureus Rosenbach (Methicillin – resistant strain) MRSA (ATCC 43300), Streptococcus pneumoniae (ATCC 33400).

Table 11D. The contact time, microbial counts in colony forming unit per mililiter (CFU/ml) controls and samples and the microbial reduction rate of Legionella pneumophila (ATCC 33152). Results show that the sample solution of the example platinum chelate solution has microbial reduction rates of 99.28%, 98.93%, 99.45%, 99.80%, 99.64% and 99.34% against Aspergillus niger (ATCC 16404), Candida albicans (ATCC 10231), Escherichia coli (ATCC 8739), Klebsiella pneumonia (ATCC 33495), Staphylococcus aureus subsp. Aureus Rosenbach (Methicillin – resistant strain) MRSA (ATCC 43300), Streptococcus pneumoniae (ATCC 33400), respectively, with a contact time of 15 minutes. Results show that the example platinum chelate solution has microbial reduction rate of 99.01% against Legionella pneumophila (ATCC 33152) (Tables 11A-11D), with a contact time of 10 minutes. In summary, the example platinum chelate solution has excellent antimicrobial effectiveness against various types of microbes including mould, yeasts, Gram positive / negative or aerobic / anaerobic bacteria. EXAMPLE 14 Sample solution: The chelate sample solution (Compound (XIII) at about 4ppm was prepared. REMOVAL EFFICIENCY OF FORMALDEHYDE IN AMBIENT AIR Test Method: The removal efficiency of formaldehyde was performed with sample solution according to Methods for determination of purificatory effect of indoor environment decontamination product (QB/T 2761-2006) and Standard Test Method for Determination of Formaldehyde and Other Carbonyl Compounds in Air (Active Sampler Methodology) (ASTM D-5197- 16). Test results: The formaldehyde concentrations of control and samples at time 0, 15, 30, 45, and 60 minutes and the calculated removal efficiency (%) were summarized in Table 12.

Table 12. Formaldehyde concentrations of control and samples over 0-60 minutes and the % of removal at 60 minutes. Results show that the formaldehyde removal efficiency of the example platinum chelate solution is 83% after 60 minutes, and majority of the formaldehyde was removed within the first 15 minutes, indicating the outstanding volatile organic compounds (VOCs) (such as formaldehyde) removal efficiency of the example platinum chelate solution. PERFORMANCE OF PLATINUM CHEALTE AS AEROSOL SPRAY EXAMPLE 15 FIELD TEST IN AN EXHIBITION VENUE (TOILET AREA) Test Preparation: Different sets agar plates for twenty swab test samples were sampled before and after treating an example platinum chelate solution on-site in an exhibition venue located in Hong Kong. The test samples were refrigerated during delivery. Platinum chelate solution sample: Chelated platinum solution (Compound XIII) was prepared according to method described in EXAMPLE 4 and diluted with water to about 12ppm. Treatment: The example platinum chelate solution was misted using a Time Medical Intelligent Sterilization Robot (Time Medical Systems) according to the manufacturer’s protocol as a treatment. Test samples were sampled before and after the treatment. Test Method: For Swab Samples: The surface bacterial count were conducted according to Practical Food Microbiology, 5.10, with reference to FDA Bacteriological Analytical Manual (BAM) Online (Jan. 2001) Chapter 3 (Conventional Plate Count Method) was used to test for surface bacteria count for swab samples. The incubation condition is 35°C for 48 hours. Test Results: Before and after test for surface bacteria count in toilet area Four different surface areas of 5cm x 5cm, hence 25cm² (toilet seat, wall of toilet compartment, door handle of toilet compartment and floor ceramic tile) were sampled. The first swab sample was collected on the selected surface before the treatment. The second to the fifth samples were collected on the selected surfaces at 15 seconds, 30 seconds, 1 minute and 30 minutes after the treatment, in order to evaluate the anti-bacterial efficiency and persistency of the example platinum chelate solution.

Table 14. Surface Bacteria Count Before and After Treatment Notes: 1. < denotes less than 2. ND denotes not detected 3. CFU/m³ denotes colony-forming unit per cubic meter For the results of airborne bacteria count: Not Detected in Sample, the detection limit is 1.0 x 101 CFU/m³ 4. CFU/cm² denotes colony-forming unit per square centimeter For the results of surface bacteria count: Not Detected in sample, the detection limit is 1.0 x 101 CFU/cm² 5. sec denotes second 6. min denotes minute Results showed that the surface bacterial counts in all the four sampling locations (toilet seat, wall of toilet compartment, door handle of toilet compartment and floor ceramic tile) significantly decreased after treating with about 12ppm chelated platinum solution (Compound XIII) for only 15 seconds, and even after treatment for 30seconds, 1 minute or 30 minutes, the surface bacterial counts only had a slight level increase or no increase at all, indicating that the antibacterial effect of the platinum chelate solution to surface bacteria on various substrates or materials is superior and long-lasting, and the action time is surprisingly fast. In summary, the above results indicates that the platinum chelate solutions not only safe for use, but have superior and long-lasting antimicrobial effects and the action time is surprisingly fast, proven in field tests. EXAMPLE 16 FIELD TEST IN AN INDOOR PUBLIC AREAS Platinum chelate solution sample: Chelated platinum solution (Compound XIII) was prepared according to method described in EXAMPLE 4 and diluted with water to about 12ppm. Treatment Preparation: TIME MEDICAL Intelligent disinfection Robot was used for misting about 12 ppm chelated platinum solution according to the manufacturer’s protocol as a treatment. Sampling site information: 10 different location points in a governmental headquarter in Hong Kong were selected for tests. Test Method: 1. Sample media with a level of concentration of E. coli was prepared and set up at each client assigned location 2. Two types of sample media a. Glass slide (placed in petri dish) b. Absorbent pad 3. E. col solution was added on each glass slice and placed at Points 1-7 and 9 4. E. col solution was added on surface of Points 8 and 10 and collected with absorbent pad 5. A total of 10 samples were prepared and underwent treatment 6. Control samples were prepared without go through any treatment a. Glass slide – Control A b. Absorbent pad – Control B 7. All samples were collected for analysis Total Bacteria Counts were conducted according to AOAC official method 18^th ed., 2005, Method 990.12 Test Results:

Table 15. Total Bacteria Count of E. coli after Treatment in Different Areas Results showed that the Total Bacteria Count of E. coli in all sampling location points significantly decreased over control after treating with about 12ppm chelated platinum solution (Compound XIII), indicating that the bactericidal effects of the platinum chelate solution on E. coli to various surfaces are superior in field tests spiked with E. coli. EXAMPLE 17 FIELD TEST IN OFFICES AND DOMESTIC AREAS Test Preparation: Fifty-five swab samples were sampled in selected offices and domestic areas located in Fotan, Hong Kong for analysis. Samples were refrigerated during delivery. Treatment: About 12ppm example chelated platinum solution (compound XIII) prepared according to method described in EXAMPLE 4 and diluted with water. The example chelated platinum solution was misted using a commercial sanitizer (uMist Dream Humidifier, OSIM) in around 80m² office area (totally 70ml example chelated platinum solution was used) and around 40-50m² domestic areas (totally 40ml example chelated platinum solution used). Test Method: For Swab Samples Surface bacterial count of the swab samples were conducted according to Practical Food Microbiology, 5.10. with reference to FDA Bacteriological Analytical Manual (BAM) Online (Jan. 2001) Chapter 3 (Conventional Plate Count Method). The incubation condition is 35°C for 48 hours. Test Results: Surface bacteria count before and after Treatment in different locations in office and domestic areas Five selected surface areas of 30cm x 15cm (wall, HVAC supply air diffuser and return air grille in the office; and floor and sleeve of occupant’s outerwear in the domestic area) were sampled. The first swab sample was collected on the selected surface before treatment. The second to the eleventh swab samples were collected on the selected surfaces at 30 seconds, 1 minute, 10 minutes, 60 minutes, 240 minutes, 480 minutes, 24 hours, 72 hours, 120 hours and 144 hours after treatment, in order to evaluate the anti-bacterial efficiency and persistency of the treatment with platinum chelate solution. Results of Surface Bacterial Count in office and domestic areas are summarized in Table 16.

Table 16. Surface Bacteria Count Before and After Treatment in Office and Domestic areas Notes: 1. < denotes less than 2. ND denotes not detected 3. CFU/m³ denotes colony-forming unit per cubic meter For the results of airborne bacteria count: Not Detected in Sample, the detection limit is 1.0 x 10¹ CFU/m³ 4. CFU/cm² denotes colony-forming unit per square centimeter For the results of surface bacteria count: Not Detected in sample, the detection limit is 1.0 x 10¹ CFU/cm² 5. sec denotes second 6. min denotes minute Results showed that the surface bacterial counts in all the sampling locations in both office and domestic areas significantly decreased after treating with about 12ppm chelated platinum solution (Compound XIII) for only 30 seconds, and even after treatment for 144 hours, the surface bacterial counts remains undetectable (<1 CFU/cm²), indicating that the antibacterial effect of the platinum chelate solution to surface bacteria on various substrates or materials in various locations is superior and surprisingly long-lasting, and the action time is surprisingly fast. In summary, the above results indicates that the platinum chelate solutions not only safe for use, but have superior and surprisingly long-lasting antimicrobial effects and the action time is surprisingly fast, proven in field tests. PLATINUM CHELATE ON FABRICS EXAMPLE 18 ANTIMICROBIAL EFFECTIVENESS ON HYDROPHILIC FABRICS Test Preparation: Fabric: An example Cotton Twill, which is a hydrophilic woven fabric useful to make gowns for doctors Platinum chelate Sample solution: an example platinum chelate solution was prepared according to method described in EXAMPLE 4 and diluted with water to about 40ppm Treatment: 150g of Cotton Twill woven Fabric was soaked in 70ml, about 40ppm chelated platinum solution (compound XIII) and allowed to air dry at room temperature. The treated fabric were tested for viable bacterial counts. Contact time: 24 hours Test Method: The Viable bacterial counts were performed according to GB 15979 – 2002, Appendix C4 Test organisms: Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538) Time interval: 24 hours Test Results: Reaction time of sample and culture inoculums: 24 hours Results of Surface Bacterial Count in office and domestic areas are summarized in Table 17.

Table 17. Bactericidal Efficacy on Treated Fabric (example cotton twill) Notes: 1. % denotes percentage 2. CFU/mL denotes colony forming units per mililiter 3. As stated in GB 15979-2002: Hygienic Standard for Disposable Sanitary Products, PRC; Appendix C4: Bactericide Efficacy rate ≥ 50%~90% indicates that the product has bacterial inhibitory effect; Bactericide Efficacy rate ≥90% indicates that the product has stronger bacterial inhibitory effect Results showed that the viable bacterial counts of both E. coli and S. aureus in the example cotton twill fabric treated with about 40ppm chelated platinum solution (compound XIII) (contact time 24 hours) has superior bactericide efficacy rates (99.98%), indicating that the hydrophilic fabric treated with platinum chelate has superior bacterial inhibitory effect. EXAMPLE 19 ANTIMICROBIAL EFFECTIVENESS ON HYDROPHOBIC FABRICS Test Preparation: Fabric: An example polyester: 145 gram/m² (gsm) 100% polyester pique knit fabric, which is a hydrophobic fabric useful in making facial masks Platinum chelate Sample solution: an example platinum chelate solution was prepared according to method described in EXAMPLE 4 and diluted with water to about 40ppm. Treatment: 45g of polyester fabric was soaked in 45ml, about 40 ppm chelated platinum (compound XIII) until the fabric is fully wet and allowed to air dry at room temperature. The treated fabric were tested for viable bacterial counts. Contact time: 24 hours Test Method: The viable bacterial counts were performed according to GB 15979 – 2002, Appendix C4 Test organism: Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538) Time interval: 24 hours Test Results: Reaction time of sample and culture inoculums: 24 hours Viable bacterial counts and bactericide efficacy were summarized in Table 18.

Table 18. Bactericide Efficacy on Treated fabric (example polyester) Notes: 1. % denotes percentage 2. CFU/mL denotes colony forming units per mililiter 3. As stated in GB 15979-2002: Hygienic Standard for Disposable Sanitary Products, PRC; Appendix C4: Bactericide Efficacy rate ≥ 50%~90% indicates that the product has bacterial inhibitory effect; Bactericide Efficacy rate ≥90% indicates that the product has stronger bacterial inhibitory effect Results showed that the viable bacterial counts of both E. coli and S. aureus in the example polyester fabric treated with about 40ppm chelated platinum solution (compound XIII) (contact time 24 hours) has superior bactericide efficacy rates (99.98% or even higher), indicating that the hydrophobic fabric treated with platinum chelate has superior bacterial inhibitory effect. In summary, results showed that various fabrics treated with platinum chelate has superior bacterial inhibitory effects. EXAMPLE 20 FAST ACTING PERFORMANCE ON FABRICS Test Preparation: Fabric: An example polyester: 145 gram/m² (gsm) 100% polyester pique knit fabric, which is a hydrophobic fabric useful in making facial masks Platinum chelate Sample solution: an example platinum chelate solution was prepared according to method described in EXAMPLE 4 and diluted with water to about 40ppm Treatment: 45g of polyester fabric was soaked in 45ml, about 40ppm chelated platinum (compound XIII) until the fabric is fully wet and allowed to air dry at room temperature. Contact time: 15 minutes The treated fabric was tested for viable bacterial counts of Staphylococcus aureus and Candida albicans. Test Method: Viable bacterial count was conducted according to GB 15979 – 2002, Appendix C4 Test organisms: Candida albicans (ATCC 10231), Staphylococcus aureus (ATCC 6538) Time interval: 15 minutes Test Results: Reaction time of sample and culture inoculums: 15 minutes

Table 19. Bactericide Efficacy on treated fabirc (example polyester) Notes: 1. % denotes percentage 2. CFU/mL denotes colony forming units per mililiter As stated in GB 15979-2002: Hygienic Standard for Disposable Sanitary Products, PRC; Appendix C4: Bactericide Efficacy rate ≥ 50%~90% indicates that the product has bacterial inhibitory effect; Bactericide Efficacy rate ≥90% indicates that the product has stronger bacterial inhibitory effect Results showed that the viable bacterial counts of both C. albicans and S. aureus in the example polyester fabric treated with about 40ppm chelated platinum solution (compound XIII) (contact time 15 minutes) has superior bactericide efficacy rates (96.04% or even higher), indicating that hydrophobic fabric treated with platinum chelate has fast action time (within 15 minutes). In summary, results showed that various fabrics treated with platinum chelate has superior bacterial inhibitory effects and fast action time. EXAMPLE 21 LONG-LASTING PERFORMANCE AND DURABILITY ON FABRICS Test Preparation: Fabric: An example polyester: 145 gram/m² (gsm) 100% polyester pique knit fabric, which is a hydrophobic fabric useful in making facial masks Platinum chelate Sample solution: an example platinum chelate solution was prepared according to method described in EXAMPLE 4 and diluted with water to about 40ppm Treatment: 45g of polyester fabric was soaked in 45ml, about 40ppm chelated platinum (compound XIII) until the fabric is fully wet and allowed to air dry at room temperature. Contact time: 24 hours Washed fabric: Chelated platinum Treated fabric sample was washed for 30 washing cycles. Each washing cycle the fabric was hand washed with 4L of room temperature double distilled water. After storage fabric: Chelated platinum Treated fabric sample was stored in a conditioned chamber at 25°C and the relative humidity (RH) of 60% for 180 days. The treated fabrics (washed and after storage for 180 days) were tested for viable bacterial counts of Escherichia coli and calculate the reduction rate (%). Test Method: The viable count was conducted according to American Association of Textile Chemists and Colorists (AATCC) Test Method 100 – 2004, Assessment of Antibacterial Finishes on Textiles Test organism: Escherichia coli (ATCC 8739) Test Results: Reaction time of sample: 24 hours Table 20 summarized the viable bacterial count reduction percentages for washed fabric and after storage fabric.

Table 20. Reduction percentages of treated fabrics (example polyester). Note:% reduction was calculated with an untreated cloth sample as control Results showed that the reduction percentages of E. coli in the example polyester fabrics treated with about 40ppm chelated platinum solution (compound XIII) (contact time 24 hours) after 30 washing cycles and after storage have superior bacterial reduction rates (96.2% or even higher), indicating that hydrophobic fabric treated with platinum chelate has surprising durability against repeated washings and long-lasting antimicrobial performance. In summary, results showed that various fabrics treated with platinum chelate has superior bacterial inhibitory effects, fast action time, surprising durability and long-lasting antimicrobial performance. EXAMPLE 22 PROPERTIES OF PLATINUM CHELATE In addition to the excellent antimicrobial properties, air purifying properties such as strong negative ion producing, strong removal efficiency of organics such as formaldehyde, and excellent safety to animals including human of the antimicrobial compounds and solutions described herein, platinum chelates are substantially colourless, unlike platinum nanoparticles being black. This greatly improves the aesthetics of the final consumer products. EXAMPLE 23 USES AND PROCESSES OF USE OF PLATINUM CHELATE Platinum chelates described herein have wide applications and they have various uses and processes of use in different aspects. In certain examples, the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate is used as a disinfectant, which can be an aerosol spray for ambient air and/or substrate surfaces. In certain examples, described is a process of using the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate described herein as a disinfectant, comprising the step of applying the disinfectant comprising the platinum chelate compounds or salts thereof, the compositions or aqueous solutions thereof to a substrate and/or ambient air in need. In one example, the disinfectant essentially consists of platinum chelate in aqueous solution. In one example, the disinfectant includes one or more platinum chelates, and optionally other metal chelates. The substrates can be selected from the group consisting of fabrics, plastics, metals, glass, wood, paper, concrete, ceramics, and combinations and composites thereof. In one example, the fabrics can be polyester or cotton. The ambient air in need can be atmosphere or spaces in indoor or outdoor conditions. In certain examples, the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate is used as a coating for any substrates or surfaces. In one example, the disinfectant is served as an aerosol spray for ambient air and/or substrate surfaces. In one example, the disinfectant is dispensed/diffused/atomized into the air (for example, as fine mists) by a dispenser, a diffuser or an atomizer. In certain examples, the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate is used as a coating for substrates/surfaces. In certain examples, described is a process of using the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate described herein as a coating for any substrates/surfaces, comprising the step of applying the coating comprising the platinum chelate compounds or salts thereof, the compositions or aqueous solutions thereof to the substrates or surfaces in need, such as plastics. Optionally, the process further comprising the step of drying the substrates or surfaces in need. The substrates can be selected from the group consisting of fabrics, plastics, metals, glass, wood, paper, concrete, ceramics, and combinations and composites thereof. In certain examples, the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate is used to remove one or more air pollutants. In certain examples, described is a process of using the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate described herein for removing one or more air pollutants, comprising the step of applying the coating comprising the platinum chelate compounds or salts thereof, the compositions or aqueous solutions thereof to the substrates and/or ambient air in need. The substrates can be selected from the group consisting of fabrics, plastics, metals, glass, wood, paper, concrete, ceramics, and combinations and composites thereof. In one example, the platinum chelate compounds or salts thereof, the compositions or aqueous solutions comprising platinum chelate described herein is dispensed/diffused/atomized into the air (for example, as fine mists) by a dispenser, a diffuser or an atomizer. In one example, the one or more air pollutants is selected from the group consisting of volatile organic compounds, microorganisms, particulates. In one example, the volatile organic compounds is formaldehyde. In one example, the particulates is Particulate Matter 2.5.In certain example, disclosed is a method of disinfecting comprising the step of contacting any one of the compounds, or salts thereof, compositions, aqueous solutions described herein with a microorganism, thereby inactivating or killing the microorganism. In certain example, disclosed is a method of removing one or more air pollutants comprising the step of applying any one of the compounds, or salts thereof, compositions, aqueous solutions described herein to the space having air pollutants, thereby removing the one or more air pollutants. By way of example, the antimicrobial compounds and solutions described herein may be used in combination of one or more other metal chelates, such as but not limited to silver chelates and copper chelates. EXAMPLE 24 ANTIMICROBIAL COMPOSITIONS COMPRISING PLATINUM CHEALTE AND SILVER CHELATE AND METHODS OF MAKING THE SAME General Procedures In certain embodiments, antimicrobial composition comprising platinum chelate and silver chelate is prepared by mixing a platinum chelate solution with a silver chelate solution. Optionally, the antimicrobial composition further comprises a stabilizing buffer to maintain the pH of the solution. In one example, to prepare an antimicrobial composition comprising platinum chelate and silver chelate, the silver tripotassium EDTA chelate solution and the platinum potassium EDTA chelate solution are mixed and make up with water at room temperature. Optionally, stabilizing buffer is added to maintain the pH above around 8.0. By way of example, the ingredients are mixed with a stirrer. Platinum chelates may be any example platinum chelates described in any previous EXAMPLES. Silver chelate preparation In certain examples, silver chelates are one or more of silver(I) tripotassium EDTA chelate, Ag(I) diammonium MGDA chelate, Ag(I) monopotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) monopotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate or Ag(I) triammonium EDTA chelate. In certain examples, silver chelates are prepared by methods known in the art. In one example, silver chelate is silver tripotassium EDTA chelate. In another example, silver chelate is silver monopotassium EDTA chelate. In another example, silver chelate is silver (I) triammonium EDTA chelate. In one example, silver chelate solution is prepared by mixing silver nitrate solution with a EDTA solution (such as tetraammonium ethylenediaminetetraacetate), and adjusting the pH to 8.0-9.5. By way of example, other suitable additives such as surfactants, adhesives and antifogging agents can be added according to the practical need. By way of example, the antimicrobial composition exclusively or essentially consists of silver chelate and platinum chelate in double distilled water. By way of example, the antimicrobial composition exclusively or essentially consists of silver EDTA chelate and platinum EDTA chelate in double distilled water. In a further example, the silver EDTA chelate is silver tripotassium chelate. In a further example, the platinum potassium EDTA chelate is platinum monopotassium EDTA chelate or platinum dipotassium EDTA chelate. By way of example, the antimicrobial composition exclusively or essentially consists of silver tripotassium EDTA chelate, platinum monopotassium EDTA chelate, and a stabilizing buffer in double distilled water. By way of example, the antimicrobial composition exclusively or essentially consists of silver tripotassium EDTA chelate, platinum diopotassium EDTA chelate, and a stabilizing buffer in double distilled water. By way of example, the aqueous antimicrobial composition exclusively or essentially consists of: a) silver tripotassium EDTA chelate about 0.0025-0.01%wt; b) platinum dipotassium EDTA chelate about 0.0025-0.01%wt; and c) a stabilizing buffer about 1-5%wt. By way of example, the stabilizing buffer can be any buffers that can maintain a pH above 8.0. For example, a buffer comprising tetraammonium ethylenediaminetetraacetate. By way of example, the chelated metals may be prepared by other chelating agents instead of EDTA. The choice of a chelating agent can be a sodium salt of, a potassium salt of, or an ammonium salt of chelating agents EDTA, DTPA, GLDA HEDTA, NTA or MGDA. By way of example, the antimicrobial compositions may be used as antimicrobial sprays, or coatings to any surfaces of objects or articles, such as but not limited to, plastics. EXAMPLE 25 ANTIMICROBIAL PROPERTIES OF ANTIMICROBIAL COMPOSITIONS COMPRISING PLATINUM CHELATE AND SILVER CHELATE ON AIR PURIFIERS In this example, antimicrobial properties of an example antimicrobial composition on airs purifiers were tested. The example antimicrobial composition comprises 40ppm platinum monopotassium EDTA chelate (compound XIII) and 19ppm silver chelate (silver (I) triammonium EDTA chelate) in solution. Platinum monopotassium EDTA chelate (compound XIII) and silver (I) triammonium EDTA chelate, prepared by general procedures described in EXAMPLE 1 and EXAMPLE 24, respectively. A total volume of 100ml of the example antimicrobial composition was sprayed onto a HEPA H13 glass fiber filter with a dimension 285mm x 285mm x 50mm using a spray bottle and left it air dry. The filter was tested for antibacterial activity assessment of textile materials according to American Association of Textile Chemists and Colorists (AATCC) Test Method 100-2019, Assessment of Antibacterial Finishes on Textiles. Test organisms: Escherichia coli (ATCC 8739), Salmonella typhimurium (ATCC 14028) and Staphylococcus aureus (ATCC 6538). Reaction time of sample and culture inoculums: 24 hours.

Table 21. Antibacterial effects of an example antimicrobial composition after 24 hour contact time. Note: CUF/mL denotes Colony Forming Unit per millilitre. Percentage of reduction is calculated as (A-B)/A x 100%. The above results showed that the HEPA H13 filter sprayed with the example antimicrobial composition has outstanding antibacterial effects (>99.99%) Escherichia coli (ATCC 8739), Salmonella typhimurium (ATCC 14028) and Staphylococcus aureus (ATCC 6538) on after a 24 hour contact time, indicating that the antimicrobial compositions comprising platinum chelate and silver chelate has outstanding antimicrobial effect on filter materials. Coating nanoparticles with antimicrobial effect onto glass fiber often requires a binding agent, this may pose an adverse effect in the air flow rate i.e. filtration efficiency. By contrast, compositions comprising chelated platinum and chelated silver has an advantage over nanoparticles, as they do not require binding agent and would not affect the air flow rate. EXAMPLE 26 ANTIMICROBIAL COMPOSITIONS COMPRISING PLATINUM CHEALTE AND S^{ILVER CHELATE AND METHODS OF MAKING THE SAME FOR PLASTICS} In this example embodiment, the example antimicrobial composition includes the following ingredients:

Table 22A. Ingredients of an example antimicrobial composition. The Ingredient 1 (Silver tripotassium EDTA chelate) is prepared by the following method: (i) mixing a silver nitrate solution with tetrapotassium ethylenediaminetetraacetatea stabilizing buffer (e.g., pH 9.0) to form a mixture at a molar ratio of about 1:4 with constant stirring; (ii) adjusting the final pH of the mixture to about pH 8.5-9.5 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; (iii) the solution is made up with double distilled water to a desired concentration. The Ingredient 2 (Platinum dipotassium EDTA chelate) is prepared by the following method: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent (e.g., ethylenediaminetetraacetic acid diapotassium salt) at a mole ratio of about 18:1 - 22:1 at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 50%(v/v) NH₄OH with the solution; (ii) adjusting the final pH of the mixture to about pH 6-10 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; and (iii) making up the solution with double distilled water to a desired concentration. Other ingredients are commercially available. Optionally, copper EDTA chelate at 0.0025-0.1%wt. is added into the compositions. In another example embodiment, the example antimicrobial composition includes the following ingredients:

Table 22B. Ingredients of an example antimicrobial composition. The Ingredient 1 (Silver(I) triammonium EDTA chelate) is prepared by the following method: (i) mixing a silver nitrate solution with tetraamonium ethylenediaminetetraacetate stabilizing buffer (e.g., pH 9.0) to form a mixture at a molar ratio of about 1:4 with constant stirring; (ii) adjusting the final pH of the mixture to about pH 8.5-9.5 with ammonium hydroxide; (iii) the solution is made up with double distilled water to a desired concentration. The Ingredient 2 (Platinum(II) EDTA chelate (or Compound XIV)) is prepared by the following method: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent (e.g., ethylenediaminetetraacetic acid diapotassium salt) at a mole ratio of about 1:1 at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 50%(v/v) NH₄OH with the solution; (ii) adjusting the final pH of the mixture to about pH 6-10 with ammonium hydroxide; and (iii) making up the solution with double distilled water to a desired concentration. Other ingredients are commercially available. Optionally, copper EDTA chelate at 0.0025-0.1%wt. is added into the compositions. To prepare the Example antimicrobial composition, the above ingredients 1-7 are mixed into ingredient 8 (double distilled water) and make up to 100% at room temperature. By way of example, the ingredients are mixed with a stirrer. By way of example, other suitable surfactants, adhesives and antifogging agents can be used instead of the examples listed above. By way of example, the above pH may be adjusted by buffer of ethylenediaminetetraacetic acid tripotassium or potassium hydroxide. By way of example, the mole ratio may be adjusted, for example, 18:1 - 22:1. By way of example, the antimicrobial composition includes at least Ingredient 1, Ingredient 2, and Ingredient 4 (stabilizing buffer) in Ingredient 8 (double distilled water). Other ingredients are optional. By way of example, the antimicrobial composition essentially consists of Ingredient 1, Ingredient 2, and Ingredient 4 (stabilizing buffer) in Ingredient 8 (double distilled water). By way of example, the aqueous antimicrobial composition essentially consists of: a) silver tripotassium EDTA chelate about 0.0025-0.01%wt; b) platinum dipotassium EDTA chelate about 0.0025-0.01%wt; and c) a stabilizing buffer (any buffers that can maintain a pH above 8.0, e.g., tetraammonium ethylenediaminetetraacetate) about 1-5%wt. By way of example, the aqueous antimicrobial composition essentially consists of: a) silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) platinum(II) EDTA chelate (or Compound XIV) about 0.0025-0.01%wt; and c) a stabilizing buffer (any buffers that can maintain a pH above 8.0, e.g., tetraammonium ethylenediaminetetraacetate) about 1-5%wt. By way of example, the chelated metals (Ingredients 1-3) may be prepared by other chelating agents instead of EDTA. The choice of a chelating agent can be a sodium salt of, a potassium salt of, or an ammonium salt of chelating agents EDTA, DTPA, GLDA HEDTA, NTA or MGDA. By way of example, the antimicrobial compositions may be used as antimicrobial coatings to any surfaces of objects or articles, such as but not limited to, plastics. EXAMPLE 27 ANTIMICROBIAL PLASTIC SHEET As an example, the example antimicrobial plastic material can be made in the form of plastic sheets. Figure 3 shows a schematic antimicrobial plastic sheet 100 before coating process, including two opposing outer plastic layers, 110a and 110b, and an inner plastic layer 120. The outer layers 110a and 110b further have outer surfaces, 112a and 112b, respectively, on which an antimicrobial composition as described herein may be coated. The inner layer 120 is sandwiched between outer layers 110a and 110b. When the outer surfaces 112a and 112b are coated with an antimicrobial composition, both sides of the plastic sheet 100 is antimicrobial. EXAMPLE 28 METHOD OF MAKING ANTIMICROBIAL PLASTIC SHEETS A. General The whole manufacturing process can be broken down into two main steps. First, prepare two preparations: (1) an Antimicrobial Composition and (2) a plastic raw material mixture. Second, use the preparations in a downstream coating processing to make antimicrobial plastic sheet. In this example embodiment, biodegradable Polyethylene Terephthalate (PET) will be used as an example of plastic raw material. As an example, the antimicrobial plastic materials is made in the form of plastic sheets by extrusion. B. Ingredients 1. Antimicrobial Composition - Chelated Platinum/Silver Mixture with or without anti-fogging agent In this example, prepare the Example Antimicrobial Composition A as described in EXAMPLE 26. 2. Plastic raw material - Polyethylene Terephthalate (PET) In this example, Polyethylene Terephthalate (CAS NO.: 25038-59-9) is used as the plastic raw material. In other example embodiments, other plastic materials including but not limited to Acrylic, Biaxially-oriented polyethylene terephthalate (BOPET), Biaxially- Oriented Polypropylene (BOPP), ethylene vinyl acetate (EVA), GAG, General purpose polystyrene (GPPS), High-density polyethylene (HDPE), High Impact Polystyrene (HIPS), Low-density polyethylene (LDPE), Polyethylene terephthalate glycol (PETG), Poly(methyl methacrylate) (PMMA), Polycarbonate (PC), Polypropylene (PP), Polyvinyl chloride (PVC) may be used. In one example, GAG is composed of three layers, with the outer layers being PETG and the middle layer being APET (amorphous polyethylene terephthalate). In certain embodiments, the plastic materials may be biodegradable plastic materials and/or derived from recyclable plastic materials. 3. Plastic raw material mixture - Polyethylene Terephthalate (PET) with biodegradable agent

Table 23. Ingredients of an example plastic raw material mixture Anti-blocking agent is used to provide air space for the final product and prevent it from being stuck together. As an example, biodegradable additive (ingredient 3) may be added to make the final product biodegradable. C. Manufacturing Flow 1. Antimicrobial Composition - Chelated Platinum /Silver ion Mixture with anti- fogging agent Platinum(II) chelate and Silver(I) chelate stock solutions are prepared. Unlike nano- particles, these metal chelates are fully ionized which significantly increase the anti- microbial efficacy. Being ions, there are three unique advantages and features. They do not reflect visible light, meaning that the transparency of the final product will not be compromised. Secondly, these ions can be evenly distributed on the plastic, which ensure total coverage. The chelated platinum /silver ion mixture may also be mixed with anti- fogging agent (described in EXAMPLE 26) to prevent fog or smog formation. Thirdly, the addition of platinum (II) chelate to silver (I) chelate also prevents the photosensitivity of silver ion under sunlight. This ensures the final product will retain its original colour for its shelflife. 2. PET Sheet Manufacturing (PET Sheet) and In-Line Coating Process (Chelated Platinum Solution with Anti-Fogging Agent) In this example embodiment, the plastic sheet 100 is composed of three layers in the form of “A/B/A” such that the plastic raw material mixture (i.e., Polyethylene terephthalate (Virgin) with additives (such as biodegradable agent & anti-blocking agent)) is dosed on “A sides” (forming two outer layers) and Polyethylene terephthalate (Virgin) is dosed on “B side” (forming an inner layer) by co-extrusion process (main /sub extrusion). Polyethylene terephthalate (Virgin) and their additives shall be dosed and weighed by calibrated auto-weighing machines respectively. The materials then shall be mixed, melted, degas/de-volatilization in main/sub extruders. The melted polymer from T-shaped die is cooled down quickly and pressed by hydraulic cylinders on several casting rollers to produce a plastic sheet. The sheet in downstream then passes through a coating machine. By way of example, the coating roller is immersed in the immersion box consisting of antimicrobial composition of 2-3 cm height. As it rotates, the coating liquid on the rollers is transferred to the sheet surface. By way of example, the antimicrobial composition is coated with a density of 1.34 g/m² to 3.05 g/m². The coated sheet with antimicrobial composition is dried by oven dryer with temperature about 70± 10 degree Celsius. The press roll is positioned (e.g., about 3cm) higher than the coating roll to prevent backflow of the antimicrobial composition. The coated sheet then shall be either reeled into rolled sheet form on winding machine or cut and stacked in flat sheet form on cutting machine. By way of example, as the coating contains adhesive and surfactant, the coating is bound onto the plastic sheet surfaces, preventing leaching of the biocides away from the plastic sheets, thus maintaining antimicrobial properties of the plastic sheets and ensuring safety to users. EXAMPLE 29 ANTIMICROBIAL PROPERTIES OF ANTIMICROBIAL COMPOSITIONS Verification of anti-bacterial properties The antibacterial test is verified by ASTM E2180 (Standard Test Method for Determining the Activity of Incorporated Antimicrobial Agent(s) In Polymeric or Hydrophobic Materials). An example antimicrobial composition A (containing both Silver(I) triammonium EDTA chelate about 50ppm and Platinum(II) EDTA chelate about 50ppm and an antifogging agent at around 10%) was prepared as described in EXAMPLE 26 (Table 22B). Another antimicrobial composition B (containing Platinum(II) EDTA chelate about 100ppm only) was prepared in similar way using the same ingredients and concentrations as described in EXAMPLE 26 (Table 22B) except that Ingredient 1 Silver(I) triammonium EDTA chelate was omitted, for comparison. The antimicrobial compositions A and B were tested with their antimicrobial activities by ASTM E2180 (Standard Test Method for Determining the Activity of Incorporated Antimicrobial Agent(s) In Polymeric or Hydrophobic Materials). The test results are shown as follows: Sample Name: Antimicrobial Composition A (5050 AFAF)

Table 24. Antimicrobial test results of Antimicrobial Composition A In summary, the Composition A can achieve a Bacterial Reduction of: >99.99% Escherichia coli (ATCC8739); and 99.99% Staphylococcus aureus (ATCC 6538). Sample Name: Antimicrobial Composition B (100 Pt.AF) (for comparison)

Table 25. Antimicrobial test results of Antimicrobial Composition B Results showed that an antimicrobial composition containing both chelated silver and chelated platinum performs surprisingly better than a composition containing chelated platinum only (i.e., without chelated silver), indicating a synergistic effect of chelated silver and chelated platinum on antimicrobial properties. EXAMPLE 30 UNEXPECTED SYNERGISTIC TECHNICAL EFFECTS OF COMBINATION OF CHELATED SILVER AND CHELATED PLATINUM The use of platinum chelates and silver chelates poses synergistic effect in antimicrobial properties. Platinum ions have high affinity towards amino acids such as histidine, cysteine and sulfide containing biomolecules such as methionine, glutathione and metallothionein. Silver ions tends to bind tightly with arginine, lysine, histidine and methionine. As a result, there are more potential binding sites exposed at the surface of a microbe. The binding of these metal ions to microbial proteins alters greatly the three-dimensional configuration of protein structure, which causes stress to the microbes and leads to cell death eventually. This explains the increase in antimicrobial efficacy when Platinum chelate and Silver chelate are used simultaneously. This kind of synergy extends to chelates of silver, copper, platinum, and palladium. In addition to the excellent antimicrobial properties, platinum chelates and silver chelates are colourless, unlike silver nanoparticles being yellow, and platinum nanoparticles being black. This greatly improves the aesthetics of the final consumer products. Downstream processing of the incorporation of biocides into or coated onto plastics often encounters the use of other reagents such as surfactants, adhesives and parting agents. EXAMPLE 31 UNEXPECTED SYNERGISTIC TECHNICAL EFFECTS OF COMBINATION OF CHELATED SILVER AND CHELATED PLATINUM IN ANTIMICRBIAL PERFORMANCE Test Preparation: Platinum chelate (3ppm) sample solution: an example platinum(II) EDTA chelate (compound XIV) solution was prepared by the method described in EXAMPLE 5 and diluted with water to about 3ppm. Silver chelate (3ppm) sample solution: an example silver (I) triammonium EDTA chelate solution was prepared by the method described in described in general procedures in EXAMPLE 24 and diluted with water to about 3ppm Platinum chelate (1.5ppm) and silver chelate (1.5ppm) sample solution: the example platinum(II) EDTA chelate (compound XIV) solution and an example silver (I) triammonium EDTA chelate solution were prepared by the method described in described in EXAMPLE 5 and general procedures in EXAMPLE 24, respectively, and mix together and diluted with water to about 1.5ppm each (i.e., final concentration of platinum chelate is about 1.5ppm and that of silver chelate is about 1.5ppm). Contact Time: contact time: 15 minutes Test Method: The bacterial reduction rates of the above three sample solutions were conducted according to ASTM E2315-2016 (contact time: 15 minutes) Test organism: Escherichia coli (ATCC 8739) Test Results:

Table 26. Antimicrobial Effectiveness of three chelate sample solutions Notes: 1. CFU/mL denotes Colony Forming Unit per milliliter 2. Bacteria Reduction Rate = (Average of controls – Average of samples) x 100 Average of controls Results showed that the bacteria reduction rates of E. coli (with contact time of 15 minutes) for platinum chelate (3ppm) sample solution, silver chelate (3ppm) sample solution and platinum chelate (1.5ppm) and silver chelate (1.5ppm) sample solution are 22.69%, 24.79% and 99.98%, respectively, indicating that the combination of platinum chelate and silver chelate has a synergistic effect on antimicrobial action. EXAMPLE 32 ANTIFOG PROPERTIES OF ANTIMICROBIAL PLASTIC SHEET In this example, antimicrobial plastic sheet with anti-fogging agent prepared as described in EXAMPLE 26 (Table 22B) as a test film. Verification of Anti-fogging properties Place the test film on about 90 °C hot water surface, and observe the ability of adhesion of water droplets at Time point after 1 minute and 5 minutes, respectively. The anti-fog effect of the plastic sheet was evaluated qualitatively. The test result is summarized as follows:

Table 27. Results of anti-fog effects on an example antimicrobial plastic sheet with anti- fogging agent Note: Scores 1-5 denoted relative anti-fog effect from “No anti-fog effect” to “Good anti- fog effect”) In summary, the antimicrobial plastic sheet with anti-fogging agent achieves good anti-fog effect. EXAMPLE 33 ANTIFOGGING PERFORMANCE OF FACIAL MASK WITH ANTIMICROBIAL PLASTIC SHEET Antimicrobial Plastic sheet: An Example Antimicrobial Composition A (without ingredient 3) (described in Table 22B in EXAMPLE 26) was prepared. This Example Antimicrobial Composition A was then applied onto PET plastic sheet to form antimicrobial plastic sheet for test (described in Example 28). Test Preparation: Facial Mask (with visible window): A medical grade facial mask with a visible window for showing the mouth area of a user was prepared. The visible window was made by the example antimicrobial plastic sheet with anti-fogging agent as described in EXAMPLE 32 (and prepared as described in EXAMPLE 26 (Table 22B). No. of Specimen: 4 pieces of Facial Masks with visible window Test Condition: 23 ± 5°C, 50% RH Test Surface: Window part of facial mask Water Bath Temperature: 50 ± 0.5°C Test Method: The resistance of fogging of oculars of the visible window of the Facial Mask was conducted according to EN 166: 2001 Clause 7.3.2 Resistance to fogging of oculars and EN 168:2001 Clause 16 test for resistance to fogging of oculars. Sample Preconditioning: 1-2 hours in distilled water at 23 ± 5°C, then dabbed dry and then conditioned in air for at least 12 hours at 23 ± 5°C, 50% RH Passing Requirement: Free from fogging for a minimum of 8 seconds when tested in accordance with clause 16 of EN 168:2001 Test Results: Result: PASS. No fogging was found within 8 seconds during test for the Visible Window of the Facial Mask, indicating that the example antimicrobial plastic sheet achieves good anti-fogging properties, useful for making visible window of a facial mask. A facial mask with a visible window made by antimicrobial plastic sheet with platinum chelate and antifogging agent is advantageous at least in that the mask will have superior antimicrobial activities, short-action time and anti-fogging action. EXAMPLE 34 ANTIMICROBIAL PERFORMANCE OF ANTIMICROBIAL PLASTIC SHEET Test Preparation: Test sample: An Example Antimicrobial Composition A (with Ingredient 3, EcoPure) (described in Table 22B in EXAMPLE 26) was prepared. This Example Antimicrobial Composition A was then applied onto PET plastic sheet (Example 28) to form antimicrobial plastic sheet for test. The example antimicrobial plastic sheet (biodegradable PET plastic sheet) coated with antimicrobial composition A (comprising platinum chelate (compound XIV), silver chelate (silver triammonium EDTA chelate) and anti-fogging agent) (Table 22B) was prepared according to method described in EXAMPLE 28. Test organisms: Escherichia coli (ATCC 8739), Klebsiella pneumoniae (ATCC 4352), Staphylococcus aureus (ATCC 6538) Test Method: Viable bacterial counts of the example antimicrobial plastic sheet were conducted according to ASTM E2180 (contact time 24 hours) and the bacterial reduction rate were calculated. Test Results: Contact time 24 hours

Table 28. Antibacterial Activity and Efficacy of example antimicrobial plastic sheet Notes: 1. CFU/mL denotes Colony Forming Unit per milliliter 2. Contact time of test specimen with inoculum is 24 hours 3. Percentage reduction = (A-B)/A x 100; Log 10 Reduction = Log (A/B) Results showed that the example antimicrobial plastic sheet (biodegradable PET plastic sheet coated with antimicrobial composition comprising platinum chelate (compound XIV), silver chelate (silver triammonium EDTA chelate) and anti-fogging agent) has a bacterial reduction rates of >99.9999% to E. coli, K. pneumoniae and S. aureus, indicating that example antimicrobial plastic sheet has a superior antimicrobial effect too various types of bacteria. EXAMPLE 35 ANTIVIRAL PERFORMANCE OF ANTIMICROBIAL PLASTIC SHEET Test Preparation: Test specimen: An Example Antimicrobial Composition A (with Ingredient 3, EcoPure) (described in Table 22B in EXAMPLE 26) was prepared. This Example Antimicrobial Composition A was then applied onto PET plastic sheet (Example 28) to form antimicrobial plastic sheet for test. The example antimicrobial plastic sheet (biodegradable PET plastic sheet) coated with antimicrobial composition A (comprising platinum chelate (compound XIV), silver chelate (silver triammonium EDTA chelate) and anti-fogging agent) (Table 22B) was prepared according to method described in EXAMPLE 28. Test organisms: Influenza A virus (A/PR8/34(H1N1)) Host cell: MCK Test Method: The antiviral activity tests were conducted according to ISO 21702:2019 Measurement of antiviral activity on plastics and other non-porous surfaces. Test Results:

Table 29. Antiviral activity test for BIODEGRADABLE PET SHEET WITH ANTI- BACTERIA AND ANTI FOG (BABF) Notes: 1. The results of the Antiviral activity rate and calculation formula as follows: Antiviral activity rate = (virus titre of reference specimen – virus titre of test specimen) / virus titre of reference specimen x 100% Results showed that the example antimicrobial plastic sheet (biodegradable PET plastic sheet) coated with antimicrobial composition A (comprising platinum chelate (compound XIV), silver chelate (silver triammonium EDTA chelate) and anti-fogging agent) has an superior antiviral activity rate of 94.34% against Influenza A virus (A/PR8/34(H1N1)), indicating that the plastic sheets coated with platinum chelate and silver chelate has a superior antiviral effect. EXAMPLE 36 ANTIMICROBAL PERFORMANCE OF NON-WOVEN FABRICS POST-TREATED WITH ANTIMICROBIAL COMPOSITION COMPRISING PLATINUM CHELATE AND SILVER CHELATE Fabric: Spunbond Meltblown Spunbond (SMS) cloth, which is a nonwoven fabric that combines spunbond and meltdown polypropylene fabrics. It is lightweight and has great water repelling capabilities, great durability and strength, making SMS fabric a good candidate for medical and hygiene products such as diapers, protective wear, face mask, hospital gown, wound care, filtration fabrics and much more. Platinum chelate, Silver chelate and mixture Sample solutions: A platinum chelate solution (Compound XIV) was prepared according to method described in EXAMPLE 5. A silver chelate solution (Silver (I) triammonium EDTA) was prepared by the method described in general procedures in EXAMPLE 24. A stabilizing buffer (tetraammonium ethylenediaminetetraacetate) was prepared. The silver chelate solution and the stabilizing buffer were mixed water to form an example silver chelate solution at about 25ppm. Final concentrations of silver chelate and stabilizing buffer are about 25ppm and about 0.1%, respectively. The example platinum chelate solution, example silver chelate solution and the stabilizing buffer were mixed water to form an example silver chelate and platinum chelate mixture solution at about 25ppm and about 4ppm, respectively. Final concentrations of platinum chelate, silver chelate and stabilizing buffer are 4ppm, 25ppm and 0.1%, respectively. Post-Processing Treatment: Treatment 1 (silver chelate solution, 25ppm): Total volume of 1.14ml of the example silver chelate solution (25ppm chelated silver (silver EDTA complex) and 0.1% stabilizing buffer, tetraammonium ethylenediaminetetraacetate) was sprayed onto a 15cm x 10cm test fabric Treatment 2 (silver chelate 25ppm and platinum chelate 4ppm mixture solution): Total volume of 1.14ml of the example silver chelate and platinum chelate mixture solution (about 25ppm chelated silver (silver EDTA complex), about 4ppm chelated platinum (platinum EDTA chelate, Compound XIV) and about 0.1% stabilizing buffer, tetraammonium ethylenediaminetetraacetate) was sprayed onto a 15cm x 10cm test fabric Both example chelate solutions were applied through a 10μm nozzle by an air pump onto the test fabric and allowed to air dry at room temperature, respectively. Contact time: 24 hours The bacterial count before and after treatment and the reduction rate of Treatments 1 and 2 were summarized in Table 30A and 30B, respectively Reaction time of sample and culture inoculums: 24 hours – Treatment 1

Table 30A. The bacterial count before and after treatment and the reduction rate of Treatment 1 (silver chelate solution, 25ppm) Reaction time of sample and culture inoculums: 24 hours – Treatment 2

Table 30B. The bacterial count before and after treatment and the reduction rate of Treatment 2 (silver chelate solution at about 25ppm and platinum chelate solution at about 4ppm) Results showed that the example fabric (SMS cloth) undergone post-processing treatment with 25ppm silver chelate solution and with 25ppm silver chelate and 25ppm platinum chelate have a bacterial reduction rate of 53.57%, and 80.61%, respectively, indicating that silver chelate has a good antibacterial effect on the nonwoven fabrics, and that a mixture of silver chelate and platinum chelate achieves even better antibacterial effect. Fabrics such as SMS cloth treated with platinum chelate (and silver chelate) is advantageous at least in that any bacteria filtered or accumulated on the SMS cloth would be killed, enhancing the safety of using the SMS cloth for making medical and hygiene products. In summary, antimicrobial compositions comprising chelated platinum and chelated silver can be applied to various kinds of substrates, for example, plastics such as PET sheets, biodegradable PET sheets, and Spunbond Meltblown Spunbond (SMS) by coating procedures as described herein. EXAMPLE 37 USES OR APPLICATIONS OF ANTIMICROBIAL PLASTIC SHEETS Example antimicrobial plastic sheets as described above may be used in various applications, including but not limited to: 1. Anti-bacterial mask/ face shield; 2. FDA approved food container; 3. Packaging for medical device; 4. Windows shield; 5. Shoe mat EXAMPLE 38 USES OR APPLICATIONS OF ANTIMICROBIAL COMPOSITIONS IN PLASTICS Example antimicrobial compositions as described above may be used in various applications, including but not limited to: 1. Chelated platinum and silver solutions can be coated with other plastic materials such as PETG, GAG, BOPET, BOPP, EVA, GPPS, HDPE, HIPS, LDPE, PMMA, Polycarbonate, PP, PVC, polycarbonate, Acrylic etc. for various applications. 2. Chelated platinum and silver ion solutions can be compatible with several plastic processes such as single / multi-layer plastic with single / twin screw extrusions, calendering or biaxial stretching systems, blow molding, etc. 3. Chelated platinum solutions can be mixed with anti-fog / anti-static / hard-coat agents etc. in liquid form and coated with all kind of plastics by either in-line or off-line coating/ spraying machine. The exemplary embodiments of the present invention are thus fully described. Although the description referred to particular embodiments, it will be clear to one skilled in the art that the present invention may be practiced with variation of these specific details. Hence this invention should not be construed as limited to the embodiments set forth herein. For example, certain examples described the antimicrobial plastic sheet is in three layers, but in other examples, the antimicrobial plastic sheet can be any number of plastic layer(s). For example, the antimicrobial plastic sheet is made in one single layer comprising any one of the antimicrobial composition as described herein. In other words, the plastic material mixing with an antimicrobial composition is used to make a single layer of plastic sheet. Each of the plastic layers can be made of any plastics and derived from any source. In one further example, a plastic sheet may be treated with (for example, coated with, or sprayed with, or immersed into) any one of the antimicrobial compositions described herein on one or both outermost surfaces. In other examples, one, two or even more plastic layers are formed with any one or more layers being the antimicrobial layer, for example, one, two, three, four, five, six, seven, eight, nine, ten or even more layers. For example, the inner plastic layers are in two or more layers, and they are made of different or the same plastic materials, and each inner plastic layer is (or is not) an antimicrobial plastic layer coated with antimicrobial composition. For example, the outermost two layers are antimicrobial plastic layer coated with antimicrobial composition, but the inner single or multiple layers are plastic layers without antimicrobial composition. For example, other arrangements of the inner plastic layers and antimicrobial plastic layers is also possible according to the practical need, In certain examples, the at least one plastic layer(s) contains antimicrobial compositions described herein, and/or other biocides, additives or other antimicrobial compositions know in the art. For example, in certain examples, biodegradable PET is used for making antimicrobial plastics, but in other examples, other biodegradable plastic materials can also be used. In certain examples, the antimicrobial plastic sheet is essentially made of plastic raw materials and an antimicrobial composition described herein. In certain examples, biodegradable additives are additionally added to form biodegradable plastics. In certain examples, the recycled plastic materials, pre-consumer and/or post-consumer content materials are used additionally or alternatively as the plastic materials for the plastic layer(s). In other words, each plastic layer can be made of a plastic raw material, a pre-consumer content material and/or a post-consumer content material.^{<DocRef#00258588-PW} >

Claims

CLAIMS What is claimed is: 1. A compound comprising a chelated platinum ion, or a salt thereof, wherein the platinum ion is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA.

2. The compound of claim 1, or a salt thereof, wherein the compound or the salt thereof is selected from a group consisting of platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate), Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, and platinum(II) EDTA chelate.

3. The compound of claim 1, or a salt thereof, having the following formula: wherein X⁺ is a cation.

4. The compound of claim 3, wherein the cation is a monovalent cation selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺.

5. The compound of claim 1, or a salt thereof, having the following formula:

(Formula II), wherein X⁺ and Y⁺ are cations, respectively.

6. The compound of claim 5, wherein each of the cations of X⁺ and Y⁺ is a monovalent cation selected from a group consisting of H⁺, Na⁺, K⁺ and NH₄ ⁺.

7. The compound of claim 5, wherein X⁺ is H⁺ or K⁺, and Y⁺ is H⁺.

8. The compound of claim 1, or a salt thereof, having the following formula:

(Compound XV).

9. The compound of claim 1, or a salt thereof, having the following formula:

(Compound XVI).

10. A composition comprising a compound of any one of claims 1 to 9, or a salt thereof.

11. An aqueous solution comprising a platinum chelate, or a salt thereof, wherein platinum is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA.

12. The aqueous solution of claim 11, wherein the platinum chelate or a salt thereof is selected from a group consisting of platinum(II) diammonium EDTA chelate, platinum(II) dipotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, and platinum(II) EDTA chelate.

13. The aqueous solution of claim 11, wherein the platinum chelate or a salt thereof is a compound of any one of claims 1 to 9, or a salt thereof.

14. The aqueous solution of any one of claims 11-13 having a pH of about pH 6-10.

15. A method of preparing an aqueous solution, comprising the steps of: (i) dissolving a platinum salt slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with a chelating agent at a suitable mole ratio at a temperature about 95°C for about 24 hours with stirring; (iii) mixing an alkaline with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10; and (v) making up the solution with double distilled water to a desired concentration.

16. The method of claim 15, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA.

17. The method of claim 15, wherein the chelating agent is ethylenediaminetetraacetic acid dipotassium salt.

18. The method of claim 15, wherein the platinum salt is a sodium salt of, a potassium salt of, a nitrate salt of, a chloride salt of, or an ammonium salt of platinate.

19. The method of claim 15, wherein the platinum salt is a platinum (IV) nitrate, platinum(IV) chloride, tetraammineplatinum(II) nitrate, chloroplatinic acid hexahydrate, ammonium chloroplatinate, dichlorodiammineplatinum(II), potassium hexachloroplatinate (IV), potassium tetrachloroplatinate(II), tetraammineplatinum(II) chloride hydrate.

20. The method of claim 15, wherein the platinum salt is the compound of any one of claims 1 to 9, or a salt thereof.

21. The method of claim 15, wherein the suitable mole ratio is about 18:1 – 22:1.

22. The method of claim 15, wherein the suitable mole ratio is about 1:1.

23. The method of claim 15, wherein the alkaline is 25-50%(v/v) NH₄OH, KOH or NaOH.

24. The method of claim 15, wherein the platinum salt is potassium hexachlotoplatinate (IV).

25. A method of preparing an aqueous solution, comprising the steps of: (i) dissolving potassium hexachlotoplatinate (IV) slowly in about 100°C double distilled water in a temperature regulated at 90°C-95°C until the solid chemical is completely dissolved to form a solution; (ii) mixing the solution with ethylenediaminetetraacetic acid dipotassium salt at a suitable mole ratio of about 1:1at a temperature about 95°C for about 24 hours with stirring; (iii) mixing 25%(v/v) NH₄OH with the solution; (iv) adjusting the final pH of the mixture to about pH 6-10 with ethylenediaminetetraacetic acid dipotassium or potassium hydroxide; and (v) making up the solution with double distilled water to a desired concentration.

26. An aqueous solution prepared by the method of any one of claims 15-25.

27. A use of the compound of any one of claims 1 to 9, or a salt thereof, or the composition of claim 10, or the aqueous solution of any one of claims 11-14 as a disinfectant.

28. The use of claim 27, wherein the disinfectant is an aerosol spray for ambient air and/or substrate surfaces.

29. The use of claim 27, wherein the disinfectant is a coating for substrates.

30. The use of claim 29, wherein the substrates is selected from the group consisting of fabrics, plastics, metals, glass, wood, paper, concrete, ceramics, and combinations and composites thereof.

31. The use of claim 30, wherein the fabrics is selected from the group consisting of polyester and cotton.

32. A use of the compound of any one of claims 1 to 9, or a salt thereof, or a composition of claim 10, or the aqueous solution of any one of claims 11-14 and 26 for removing one or more air pollutants.

33. The use of claim 32, wherein the one or more air pollutant is selected from the group consisting of volatile organic compounds, microorganisms, particulates.

34. The use of claim 33, wherein the volatile organic compounds is formaldehyde.

35. The use of claim 34, wherein the particulates is Particulate Matter 2.5.

36. A composition comprising the compound of any one of claims 1 to 9, or a salt thereof, wherein the composition further comprises silver chelate.

37. An aqueous solution comprising a platinum chelate and a silver chelate.

38. The aqueous solution of claim 37, wherein the platinum chelate is chelated with a chelating agent and the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, MGDA, HEDTA, or NTA.

39. The aqueous solution of claim 37, wherein the platinum chelate, or a salt thereof, is selected from the group consisting of Pt(II) diammonium EDTA chelate, platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, platinum(II) monopotassium EDTA chelate, or platinum(II) EDTA chelate.

40. The aqueous solution of claim 37, wherein the platinum chelate is a compound of any one of claims 3 to 9, or a salt thereof.

41. The aqueous solution of any one of claims 37-40, wherein the silver chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA.

42. The aqueous solution of any one of claims 37-41, wherein the silver chelate, or a salt thereof, is selected from a group consisting of silver(I) tripotassium EDTA chelate, Ag(I) diammonium MGDA chelate, Ag(I) monopotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) monopotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate, and Ag(I) triammonium EDTA chelate.

43. An aqueous antimicrobial composition, comprising: a) a silver chelate about 0.0025-2%wt; b) a platinum chelate about 0.0025-2%wt; and c) a stabilizing buffer about 1-5%wt.

44. The aqueous antimicrobial composition of claim 43, wherein the silver chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA.

45. The aqueous antimicrobial composition of any one of the preceding claims, wherein the platinum chelate is chelated with a chelating agent, wherein the chelating agent is a sodium salt of, a potassium salt of, or an ammonium salt of EDTA, DTPA, GLDA, HEDTA, NTA or MGDA.

46. The aqueous antimicrobial composition of any one of the preceding claims, wherein the silver chelate is selected from a group consisting of silver chelate, silver(I) tripotassium EDTA, Ag(I) diammonium MGDA chelate, Ag(I) dipotassium MGDA chelate, Ag(I) tetrapotassium chelate, Ag(I) tetraammonium chelate, Ag(I) dipotassium NTA chelate, Ag(I) diaamonium NTA chelate, Ag(I) tripotassium HEDTA chelate, Ag(I) triammonium HEDTA chelate, Ag(I) tripotassium GLDA chelate, Ag(I) triammonium GLDA chelate and Ag(I) triammonium EDTA chelate.

47. The aqueous antimicrobial composition of any one of the preceding claims, wherein the platinum chelate is selected from a group consisting of platinum(II) diapotassium EDTA chelate, Pt(II) potassium MGDA chelate, Pt(II) ammonium MGDA chelate, Pt(II) tripotassium DTPA chelate, Pt(II) triammonium DTPA chelate, Pt(II) potassium NTA chelate, Pt(II) ammonium NTA chelate, Pt(II) dipotassium HEDTA chelate, Pt(II) diammonium HEDTA chelate, Pt(II) dipotassium GLDA chelate, Pt(II) diammonium GLDA chelate, Pt(II) diammonium EDTA chelate, platinum(II) monopotassium EDTA chelate, or Platinum(II) EDTA.

48. The aqueous antimicrobial composition of any one of the preceding claims, wherein the stabilizing buffer maintains pH of the composition above 8.0.

49. The aqueous antimicrobial composition of any one of the preceding claims, wherein a) Silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) Platinum(II) EDTA chelate (e.g., Compound XIV) about 0.0025-0.01%wt; and c) tetraammonium ethylenediaminetetraacetate about 1-5%wt.

50. The aqueous antimicrobial composition of any one of the preceding claims, further comprising a surfactant about 0.1-0.3%wt.

51. The aqueous antimicrobial composition of any one of the preceding claims, wherein the surfactant is Tergopren 5840 and/or BYK-300.

52. The aqueous antimicrobial composition of any one of the preceding claims, further comprising an adhesive about 0.5-2.0%wt.

53. The aqueous antimicrobial composition of claim 52, wherein the adhesive is Xiameter OFS-6040 Silane, and/or Eastman 347W.

54. The aqueous antimicrobial composition of any one of the preceding claims, further comprising an anti-fogging agent about 10-20%wt.

55. The aqueous antimicrobial composition of claim 54, wherein the anti-fogging agent is MECOSTAT-3/722 and/or PETAFD-20.

56. The aqueous antimicrobial composition of any one of the preceding claims, further comprising a biocide.

57. The aqueous antimicrobial composition of claim 56, wherein the biocide is copper EDTA chelate 0.0025-0.1%wt.

58. The aqueous antimicrobial composition of any one of the preceding claims, wherein the composition is made up with double distilled water.

59. An aqueous antimicrobial composition, comprising: a) Silver(I) triammonium EDTA chelate about 0.0025-0.01%wt; b) Platinum(II) EDTA chelate chelate about 0.0025-0.01%wt; c) tetraammonium ethylenediaminetetraacetate about 1-5%wt; d) a surfactant (e.g., Tergopren 5840 and/or BYK-300) about 0.5-2.0%wt; e) an adhesive (e.g. Xiameter OFS-6040 Silane and/or Eastman 347W) about 0.5- 2.0%wt; and f) an antifogging agent (e.g., MECOSTAT-3/722, PETAFD-20) about 10-20%wt, wherein the composition is made up with double distilled water to 100% and wherein the composition optionally comprises copper EDTA chelate 0.0025-0.1%wt.

60. An antimicrobial plastic sheet comprising the aqueous antimicrobial composition of any one of the preceding claims; and optionally the at least one surface of the antimicrobial plastic sheet is treated with (e.g., coated with, sprayed with, or immersed into) the aqueous antimicrobial composition.

61. The antimicrobial plastic sheet of claim 60, comprising: (a) at least one plastic layer; and (b) a top antimicrobial plastic layer and/or a bottom antimicrobial plastic layer, wherein the at least one plastic layer is sandwiched between the top and the bottom antimicrobial plastic layers, the top antimicrobial plastic layer and/or the bottom antimicrobial plastic layer is/are treated with (e.g., coated with, sprayed with or immersed into) the antimicrobial composition as claimed in any one of the preceding claims such that at least one outer surface of the antimicrobial plastic sheet is antimicrobial.

62. The antimicrobial plastic sheet of claim 61, wherein the at least one plastic layer is made of a plastic raw material, a pre-consumer content material and/or a post-consumer content material, and the top antimicrobial plastic layer and/or the bottom antimicrobial plastic layer is/are made of a plastic raw material mixture, a pre-consumer content material and/or a post-consumer content material.

63. The antimicrobial plastic sheet of claim 62, wherein the plastic raw material is Acrylic, APET, BOPET, BOPP, EVA, GAG, GPPS, HDPE, HIPS, LDPE, PETG, PMMA, Polycarbonate, PP and/or PVC.

64. The antimicrobial plastic sheet of claim 62, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%.

65. The antimicrobial plastic sheet of claim 62, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g. EcoPure) about 0-3%wt.

66. A method of preparing an antimicrobial plastic sheet, comprising the steps of: (i) co-extruding a plastic raw material and a plastic raw material mixture comprising the plastic raw material and additives (e.g., anti-blocking agent, silicone dioxide and biodegradable additive) together to form a plastic sheet, wherein the plastic raw material forms an inner plastic layer and the plastic raw material mixture forms two outer plastic layers such that the inner plastic layer is sandwiched between the two outer plastic layers; and (ii) coating a layer of the antimicrobial composition as claimed in any one of the preceding claims onto the outer surface of the outer plastic layer to form an antimicrobial surface, such that the plastic sheet become antibacterial.

67. The method of claim 66, wherein the plastic raw material is Polyethylene Terephthalate (PET) and the plastic raw material mixture comprises: (a) an anti-blocking agent (e.g., Ester Waxes) and silicone dioxide, wherein the sum of the anti-blocking agent and silicone dioxide is about 0-3%wt; and (b) Polyethylene Terephthalate, added to 100%.

68. The methods of any one of claims 66-67, wherein the plastic raw material mixture further comprises a biodegradable additive (e.g.EcoPure) 0-3%wt.

69. The method of any one of claims 66-68, wherein the step (ii) further comprising the steps of: (1) dosing and weighing the first raw material mixture and the second raw material mixture; (2) mixing, melting, degassing, and de-volatilizing the first and second raw material mixtures to form melted, first polymer and second polymer; and (3) cooling and pressing the first and second polymers from a T-shaped die to form a plastic sheet.

70. The method of preparing an antimicrobial plastic sheet of any one of claims 66-69, further comprising the step of: (4) drying the plastic sheet at about 70± 10 °C. ^{<DocRef#00258588-PW >}