CN113671095A - Titration method of vitamin C in solid preparation - Google Patents
Titration method of vitamin C in solid preparation Download PDFInfo
- Publication number
- CN113671095A CN113671095A CN202110958238.5A CN202110958238A CN113671095A CN 113671095 A CN113671095 A CN 113671095A CN 202110958238 A CN202110958238 A CN 202110958238A CN 113671095 A CN113671095 A CN 113671095A
- Authority
- CN
- China
- Prior art keywords
- vitamin
- solution
- sample
- titration
- iodometric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 title claims abstract description 114
- ZZZCUOFIHGPKAK-UHFFFAOYSA-N D-erythro-ascorbic acid Natural products OCC1OC(=O)C(O)=C1O ZZZCUOFIHGPKAK-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 229930003268 Vitamin C Natural products 0.000 title claims abstract description 56
- 235000019154 vitamin C Nutrition 0.000 title claims abstract description 56
- 239000011718 vitamin C Substances 0.000 title claims abstract description 56
- 238000004448 titration Methods 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 239000007787 solid Substances 0.000 title claims abstract description 13
- 239000000243 solution Substances 0.000 claims abstract description 33
- UEZVMMHDMIWARA-UHFFFAOYSA-N Metaphosphoric acid Chemical compound OP(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000007864 aqueous solution Substances 0.000 claims abstract description 17
- 239000000843 powder Substances 0.000 claims abstract description 15
- 229920002472 Starch Polymers 0.000 claims abstract description 13
- 235000019698 starch Nutrition 0.000 claims abstract description 13
- 239000008107 starch Substances 0.000 claims abstract description 13
- 238000005303 weighing Methods 0.000 claims abstract description 13
- 239000007902 hard capsule Substances 0.000 abstract description 2
- 239000003826 tablet Substances 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 12
- 239000011782 vitamin Substances 0.000 description 9
- 229940088594 vitamin Drugs 0.000 description 9
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 235000016709 nutrition Nutrition 0.000 description 6
- 101001013797 Homo sapiens Metallothionein-1L Proteins 0.000 description 5
- 102100031782 Metallothionein-1L Human genes 0.000 description 5
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 4
- 239000011707 mineral Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000002775 capsule Substances 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- 229910001447 ferric ion Inorganic materials 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229930003231 vitamin Natural products 0.000 description 3
- 235000013343 vitamin Nutrition 0.000 description 3
- 150000003722 vitamin derivatives Chemical class 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000005562 fading Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 235000013402 health food Nutrition 0.000 description 2
- 239000011630 iodine Substances 0.000 description 2
- 229910052740 iodine Inorganic materials 0.000 description 2
- FSXQWAWHSKBUFH-UHFFFAOYSA-M sodium;2,3-dichlorophenolate Chemical compound [Na+].[O-]C1=CC=CC(Cl)=C1Cl FSXQWAWHSKBUFH-UHFFFAOYSA-M 0.000 description 2
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 235000010323 ascorbic acid Nutrition 0.000 description 1
- 239000011668 ascorbic acid Substances 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- GORBWKHYCDIEIF-UHFFFAOYSA-N azanium;pyrrolidine;carbamodithioate Chemical compound [NH4+].NC([S-])=S.C1CCNC1 GORBWKHYCDIEIF-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- -1 ferric iron ions Chemical class 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035764 nutrition Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229960003330 pentetic acid Drugs 0.000 description 1
- 230000008569 process Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/16—Injection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Plasma & Fusion (AREA)
- Engineering & Computer Science (AREA)
- Medicinal Preparation (AREA)
Abstract
The invention discloses a titration method of vitamin C in a solid preparation, which comprises the steps of precisely weighing 0.1-2.5 g of a sample (equivalent to 100-200 mg of vitamin C) ground into fine powder in a conical flask, adding 100-200 ml of metaphosphoric acid aqueous solution, shaking to dissolve, adding 1-2 ml of starch indicator, immediately titrating with iodometric solution to dark blue or dark brown, keeping the solution fadeless for 30s, and calculating the content of the vitamin C in the sample according to the titration volume. The titration method provided by the invention is simple and convenient to operate, short in testing time and high in accuracy, and is suitable for measuring vitamin C in solid preparations such as tablets, hard capsules, powder, premix and the like.
Description
Technical Field
The invention relates to the field of detection of functional components of health-care food, food or medicine, in particular to a titration detection method for the content of vitamin C in a solid preparation containing a ferric iron component.
Background
Vitamin C, a water-soluble vitamin, also known as ascorbic acid, is a polyhydroxy compound with acidic properties, has strong reducibility and is easily oxidized into dehydrovitamin C.
At present, the titration methods of vitamin C mainly comprise an iodine titration method and a sodium dichlorophenolate titration method, the sodium dichlorophenolate titration method is complex in operation and long in detection period, and although the iodine titration method is simple and convenient to operate and short in time, for products containing various components, particularly ferric iron, the vitamin C is easily oxidized by the ferric iron due to the strong oxidizing property of the ferric iron, so that the titration result is low, and the actual content of the vitamin C in the products cannot be accurately determined. The method for detecting vitamin C in multi-component health food disclosed at present, for example, in the patent of 'identification method of vitamin C content in vitamin mineral health food' of Jiangsu Elaland nutrient Co., Ltd (application No. 201210450128.9), which uses diethylenetriamine pentaacetic acid and pyrrolidine ammonium dithiocarbamate as metal ion masking agents, but the method cannot mask ferric iron ions, and the used sulfuric acid has strong corrosivity.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the titration method can effectively mask the influence of ferric ions on vitamin C, and accurately, efficiently and conveniently detect the vitamin C in the solid preparation.
The technical scheme adopted by the invention for solving the technical problems is as follows: a titration method of vitamin C in a solid preparation is characterized in that: accurately weighing 0.1-2.5 g of a sample (equivalent to 100-200 mg of vitamin C) ground into fine powder in an erlenmeyer flask, adding 100-200 ml of metaphosphoric acid aqueous solution, shaking to dissolve, adding 1-2 ml of starch indicator, immediately titrating with iodometric solution to dark blue or dark brown, keeping the solution for 30s, and calculating the content of the vitamin C in the sample according to the titration volume.
The calculation formula of the content of the vitamin C is as follows:
in the formula, C: the concentration of the iodometric solution is unit mol/L;
v: volume of iodometric solution consumed, in ml;
w: the samples were weighed in g.
The concentration of the metaphosphoric acid aqueous solution is 20-60 g/L.
The concentration of the iodometric solution is 0.05 mol/L.
The method has the advantages that the metaphosphoric acid aqueous solution is used as the extraction solvent of the sample, the metaphosphoric acid can effectively mask the influence of ferric ions on vitamin C, the stability of the vitamin C in the solvent is improved, the metaphosphoric acid is stable in property and non-volatile, and cannot be decomposed under the conventional condition.
Drawings
Figure 1 is a comparison of the recovery using the present method with the results of the conventional pharmacopoeia method for examples 7-10.
Detailed Description
The present invention will now be described in further detail with reference to examples.
Example 1:
precisely weighing 1.1g of a sample (about equivalent to 100mg of vitamin C, product name: Fe, Zn and multi-vitamin tablets, code: MT1L, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 20g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating according to the titration volume to obtain that the content of the vitamin C in the sample is 65.1 mg/g.
Example 2:
precisely weighing 1.1g of a sample (about equivalent to 100mg of vitamin C, product name: Fe, Zn and multi-vitamin tablets, code: MT1L, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 40g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating according to the titration volume to obtain that the content of the vitamin C in the sample is 65.2 mg/g.
Example 3:
precisely weighing 1.1g of a sample (about equivalent to 100mg of vitamin C, product name: Fe, Zn and multi-vitamin tablets, code: MT1L, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 60g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating according to the titration volume to obtain that the content of the vitamin C in the sample is 65.2 mg/g.
Example 4:
precisely weighing 1.5g of a sample (about 100mg of vitamin C, product name: Fe + vitamin C capsule, code: MTPF, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 20g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating the content of the vitamin C in the sample to be 86.3mg/g according to the titration volume.
Example 5:
precisely weighing 1.5g of a sample (about 100mg of vitamin C, product name: Fe + vitamin C capsule, code: MTPF, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 40g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating the content of the vitamin C in the sample to be 86.3mg/g according to the titration volume.
Example 6:
precisely weighing 1.5g of a sample (about 100mg of vitamin C, product name: Fe + vitamin C capsule, code: MTPF, source: Jiangsu Ailan nutritional products Co., Ltd.) which is ground into fine powder, adding 100ml of 60g/L aqueous solution of metaphosphoric acid into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating the content of the vitamin C in the sample to be 86.2mg/g according to the titration volume.
Examples 1-3 and 4-6 the content of vitamin C in MT1L and MTPF of the samples (the determination results are shown in the following table), respectively, were maintained at about 65.2mg/g for MT1L and about 86.3mg/g for MTPF, and the conclusion was that: the concentration of metaphosphoric acid in the same sample had a negligible effect on the results of the vitamin C assay.
And the content of the vitamin C in the two samples is measured by adopting a traditional pharmacopoeia detection method (namely dilute acetic acid is adopted as an extraction solvent), and the recovery rate is calculated, and compared with the measurement result of the method, the method has the following steps:
as can be seen from the table above, in the process of developing the method, the metaphosphoric acid aqueous solution is used as the extraction solvent of the sample, so that the influence of ferric ions on vitamin C can be effectively masked, the content determination of the vitamin C in the solid preparation is more accurate, and the recovery rate is higher.
Example 7:
precisely weighing 2.5g of a powder sample (product name: multi-vitamin mineral powder, code: OP51, source: Jiangsu Elaland nutriment Co., Ltd.) ground into fine powder, adding 100ml of 60g/L metaphosphoric acid aqueous solution into a 250ml conical flask, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric titration solution, titrating to dark blue or dark brown, keeping the solution for 30s, and calculating according to the titration volume to obtain the content of vitamin C in the sample to be 35.9 mg/g.
Example 8:
precisely weighing 0.7g of a finely ground premix sample (product name: vitamin complex premix, code: VP05, source: Jiangsu Elatio Nutrition Co., Ltd.) in a 250ml conical flask, adding 100ml of 40g/L aqueous solution of metaphosphoric acid, shaking for dissolution, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric titration solution, titrating to dark blue or dark brown, keeping the solution from fading for 30s, and calculating according to the titration volume to obtain the content of vitamin C in the sample of 140.7 mg/g.
Example 9:
precisely weighing 2.5g of a tablet sample (product name: multi-vitamin mineral tablet, code: DD9945, source: Hewlett-packard pharmaceutical company, Ltd.) ground into fine powder into a 250ml conical flask, adding 100ml of 60g/L aqueous solution of metaphosphoric acid, shaking to dissolve, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric titration solution to dark blue or dark brown, keeping the solution from fading for 30s, and calculating according to the titration volume to obtain the content of the vitamin C in the sample to be 36.3 mg/g.
Example 10:
precisely weighing 0.9g of a finely ground tablet sample (product name: multi-vitamin mineral tablet, code: S120123, source: Zhejiang New Vision Biotechnology Ltd.) in a 250ml conical flask, adding 100ml of 20g/L metaphosphoric acid aqueous solution, shaking for dissolving, adding 1ml of starch indicator, immediately titrating with 0.05mol/L iodometric solution, titrating to dark blue or dark brown, keeping the solution for 30S, and calculating according to the titration volume to obtain the content of vitamin C in the sample of 111.5 mg/g.
In examples 7 to 10, the method is used to perform titration detection of vitamin C content on samples of different forms and different sources (the recovery rate is compared with the results of the conventional pharmacopoeia method and is shown in figure 1), and it can be seen that the detection recovery rate of vitamin C can be effectively improved in the concentration range of 20-60 g/L in the metaphosphoric acid solution, so that the content of vitamin C in the product can be truly reflected.
The titration method provided by the invention is simple and convenient to operate, short in testing time and high in accuracy, and is suitable for measuring vitamin C in solid preparations such as tablets, hard capsules, powder, premix and the like.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (4)
1. A titration method of vitamin C in a solid preparation is characterized in that: accurately weighing 0.1-2.5 g of a sample (equivalent to 100-200 mg of vitamin C) ground into fine powder in an erlenmeyer flask, adding 100-200 ml of metaphosphoric acid aqueous solution, shaking to dissolve, adding 1-2 ml of starch indicator, immediately titrating with iodometric solution to dark blue or dark brown, keeping the solution for 30s, and calculating the content of the vitamin C in the sample according to the titration volume.
2. The titration method of vitamin C in a solid preparation according to claim 1, wherein: the calculation formula of the content of the vitamin C is as follows:
in the formula, C: the concentration of the iodometric solution is unit mol/L;
v: volume of iodometric solution consumed, in ml;
w: the samples were weighed in g.
3. The titration method of vitamin C in a solid preparation according to claim 1, wherein: the concentration of the metaphosphoric acid aqueous solution is 20-60 g/L.
4. The titration method of vitamin C in a solid preparation according to claim 1, wherein: the concentration of the iodometric solution is 0.05 mol/L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110958238.5A CN113671095A (en) | 2021-08-20 | 2021-08-20 | Titration method of vitamin C in solid preparation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110958238.5A CN113671095A (en) | 2021-08-20 | 2021-08-20 | Titration method of vitamin C in solid preparation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113671095A true CN113671095A (en) | 2021-11-19 |
Family
ID=78544175
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110958238.5A Pending CN113671095A (en) | 2021-08-20 | 2021-08-20 | Titration method of vitamin C in solid preparation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113671095A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070099174A1 (en) * | 2005-11-03 | 2007-05-03 | Bob Han | Rapid Testing for Nutrients |
| CN103091449A (en) * | 2012-11-13 | 2013-05-08 | 江苏艾兰得营养品有限公司 | Method for identifying vitamin C content in vitamin/mineral health product |
| CN105651878A (en) * | 2015-12-31 | 2016-06-08 | 苏州科铭生物技术有限公司 | Kit and method for measuring content of ascorbic acid |
| CN106841512A (en) * | 2016-12-23 | 2017-06-13 | 东北制药集团沈阳第制药有限公司 | A kind of method for detecting VC contents in vitamin C solid beverage |
| CN108414256A (en) * | 2018-01-15 | 2018-08-17 | 青岛海尔股份有限公司 | A kind of detection method of fridge freshness retaining performance |
-
2021
- 2021-08-20 CN CN202110958238.5A patent/CN113671095A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070099174A1 (en) * | 2005-11-03 | 2007-05-03 | Bob Han | Rapid Testing for Nutrients |
| CN103091449A (en) * | 2012-11-13 | 2013-05-08 | 江苏艾兰得营养品有限公司 | Method for identifying vitamin C content in vitamin/mineral health product |
| CN105651878A (en) * | 2015-12-31 | 2016-06-08 | 苏州科铭生物技术有限公司 | Kit and method for measuring content of ascorbic acid |
| CN106841512A (en) * | 2016-12-23 | 2017-06-13 | 东北制药集团沈阳第制药有限公司 | A kind of method for detecting VC contents in vitamin C solid beverage |
| CN108414256A (en) * | 2018-01-15 | 2018-08-17 | 青岛海尔股份有限公司 | A kind of detection method of fridge freshness retaining performance |
Non-Patent Citations (5)
| Title |
|---|
| INTISAR EL SHARAA 等: "Determination of Vitamin C (Ascorbic Acid) Contents in Vegetable Samples by UV-Spectrophotometry and Redox Titration Methods and Estimation the Effect of Time, Cooking and Frozen on Ascorbic Acid Contents", 《INTERNATIONAL JOURNAL OF PROGRESSIVE SCIENCES AND TECHNOLOGIES》 * |
| 国家药典委员会 编: "《国家药品标准 化学药品地方标准上升国家标准 第十五册》", 30 June 2003 * |
| 宋秀丽 等: "维生素C片中维生素C测定方法比较", 《太原师范学院学报（自然科学版）》 * |
| 符羽: "碘量法在Vc药片抗坏血酸含量测定中的应用", 《新教育》 * |
| 胡文玉: "维生素C的测定", 《新农业》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Shrivas et al. | Localized surface plasmon resonance of silver nanoparticles for sensitive colorimetric detection of chromium in surface water, industrial waste water and vegetable samples | |
| Cava-Montesinos et al. | Determination of As, Sb, Se, Te and Bi in milk by slurry sampling hydride generation atomic fluorescence spectrometry | |
| CN103091449B (en) | Method for identifying vitamin C content in vitamin/mineral health product | |
| Michaelis et al. | Semiquinone radicals of the thiazines | |
| CN107084960A (en) | The preparation method of carbon point fluorescence probe | |
| Erdemir | Contribution of tea (Camellia sinensis L.) to recommended daily intake of Mg, Mn, and Fe: An in vitro bioaccessibility assessment | |
| CN102707005A (en) | Method for synchronously analyzing ferric iron and ferrous iron in water sample online | |
| Ribeiro et al. | Flow-injection spectrophotometric determination of methyldopa in pharmaceutical formulations | |
| McCALL et al. | Spectrophotometric determination of copper and zinc in animal tissues | |
| CN113671095A (en) | Titration method of vitamin C in solid preparation | |
| Araya et al. | Iodine and iodate determination by a new spectrophotometric method using N, N-dimethyl-p-phenylenediamine, validated in veterinary supplements and table salt | |
| CN104236966A (en) | Method for detecting content of extractable arsenic in textile | |
| Guest | Determination of copper in metallurgical analysis | |
| CN106841512A (en) | A kind of method for detecting VC contents in vitamin C solid beverage | |
| Revanasiddappa et al. | Rapid spectrophotometric determination of chromium with trifluoperazine hydrochloride | |
| Verma | Determination of ascorbic acid with o-iodosobenzoate Analysis of mixtures of ascorbic acid with methionine and cysteine or glutathione | |
| Hassan et al. | Selective determination of thiamine (vitamin B1) in pharmaceutical preparations by direct potentiometric argentometric titration with use of the silver—silver sulphide ion-selective electrode | |
| Mubarak et al. | Highly sensitive catalytic determination of molybdenum | |
| Lee et al. | Spectrophotometric determination of some organic acids with ferric 5-nitrosalicylate complex | |
| Tesfaldet et al. | Sequential injection spectrophotometric determination of trace amounts of iodide by its catalytic effect on the 4, 4′-methylenebis (N, N-dimethylaniline)-chloramine-T reaction | |
| Farhadi et al. | Study of reactions of triiodide and alizarin red S with some important phenothiazines. Development of an indirect titrimetric and a spectrophotometric method for the assay of phenothiazine derivatives | |
| Walash et al. | Evaluation of certain pharmaceuticals with hexa-amminecobalt (III) tricarbonatocobaltate (III)—I: Determination of some N-substituted phenothiazine derivatives | |
| De et al. | Extraction and spectrophotometric determination of cobalt (ii) with 2-thenoyltrifluoroacetone | |
| Carmona et al. | Stopped-flow kinetic determination of acetaminophen by oxidation with a 1, 10-phenanthroline/iron (III) complex | |
| CN101493422A (en) | Method for determining magnesium content in copper-magnesium alloy |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211119 |
|
| RJ01 | Rejection of invention patent application after publication |