CN113480999B - Fluorescent metal nanocluster and preparation method and application thereof - Google Patents
Fluorescent metal nanocluster and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses a fluorescent metal nanocluster and a preparation method and application thereof, wherein the fluorescent metal nanocluster comprises a nickel metal nanostructure and a glutathione ligand, the glutathione ligand is attached to the nickel metal nanostructure through a chemical bond, the maximum fluorescence excitation wavelength is 380nm, the maximum emission wavelength is 445nm, and the fluorescent metal nanocluster has the optical characteristic of enhanced aggregation-induced fluorescence in a solvent. The preparation method is simple and convenient, easy to operate, low in cost, green and mild, and the fluorescent metal nanocluster can be used as a fluorescent probe to be subjected to fluorescent quenching by a DTC organic compound, so that the DTC organic compound can be rapidly, sensitively and specifically identified. Has potential application value in the detection of environmental water samples and pesticide residue pollutants of traditional Chinese medicines.
Description
Technical Field
The invention relates to the technical field of environmental detection and nano materials, in particular to a fluorescent metal nanocluster and a preparation method and application thereof.
Background
Dithiocarbamates (DTCs) are a class of organic compounds that can be used as fungicides and are widely used in agricultural production, particularly against fungal and insect infestation. Representative DTC pesticides include thiram, ferbam, ziram, propineb, metiram and the like, and the pesticides have the advantages of low price and low toxicity, but the dosage and the using method need to be strictly controlled. The pesticide can remain in crops, atmosphere, soil and water sources for a long time, and can cause irreversible damage to human bodies and ecological environment for a long time if the pesticide is carelessly used. The residue of DTC can be absorbed by humans through skin contact, pulmonary respiration, and gastrointestinal absorption, which can cause hepatotoxicity, immunotoxicity, peripheral neuropathy, reproductive damage, and the like. DTC can also form DTC-Cu with Cu ions in cells 2+ Complex, thereby promoting Cu-catalyzed redox cycling and thus accelerating apoptosis. The existing DTC pesticide residue detection method comprises high performance liquid chromatography, mass spectrometry, gas chromatography, chemiluminescence analysis, surface enhanced Raman scattering spectrometry and the like, and the methods generally existHigh cost, long time consumption, complex operation and the like. Therefore, the research and development of a novel method for the DTC pesticide quantitative detection which is rapid, simple and convenient and has high selectivity has very important practical significance.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The present invention aims to provide a fluorescent metal nanocluster, and a preparation method and an application thereof to improve the above technical problems.
The invention is realized in the following way:
in a first aspect, the present invention provides a fluorescent metal nanocluster including a nickel metal nanostructure and a glutathione ligand attached to the nickel metal nanostructure by a chemical bond.
In a second aspect, the present invention also provides a method for preparing the fluorescent metal nanocluster, which includes: and (3) stably synthesizing the metal nickel ions and the glutathione ligand into the fluorescent metal nanocluster.
In a third aspect, the present invention also provides a fluorescent solution comprising the above fluorescent metal nanoclusters and a solvent, optionally, the solvent comprises an alcohol, preferably ethylene glycol; optionally, the solvent has a volume content of ethylene glycol greater than or equal to 30%, preferably greater than or equal to 90%.
In a fourth aspect, the invention also provides an application of the fluorescent metal nanocluster in detection of dithiocarbamate compounds.
In a fifth aspect, the present invention also provides a method for detecting a dithiocarbamate compound, which uses the fluorescent metal nanoclusters as a fluorescent probe to detect the dithiocarbamate compound. Optionally, the fluorescent probe is mixed with the sample to be detected, and then fluorescence detection is performed, preferably, the excitation wavelength for fluorescence detection is 370-390 nm, preferably 380nm.
The technical scheme of the invention at least has the following beneficial effects: the fluorescent metal nanocluster is characterized in that glutathione and nickel ions are synthesized to form a glutathione ligand which is attached to the nickel metal nanostructure through chemical bonds, and the preparation method is simple and convenient, easy to operate, low in cost, green and mild. The fluorescent metal nanocluster can be used as a fluorescent probe and is subjected to fluorescence quenching by a DTC organic compound, so that the fluorescent metal nanocluster can be used for rapidly, sensitively and specifically identifying the DTC organic compound. The method overcomes the defects of long detection time consumption, complex steps and high cost of the existing pesticide residue detection method.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a diagram showing an ultraviolet-visible absorption spectrum, a fluorescence excitation spectrum and a fluorescence emission spectrum of GSH-Ni NCs prepared in example 1 of the present invention;
FIG. 2 is an infrared spectrum of GSH-Ni NCs prepared in example 1 of the present invention;
FIG. 3 is a transmission electron microscope image of GSH-Ni NCs prepared in example 1 of the present invention;
FIG. 4 is a graph showing the fluorescence intensity of the emission peak of GSH-Ni NCs prepared in example 1 of the present invention at a wavelength of 445nm in ethylene glycol of various ratios;
FIG. 5 is a linear relationship diagram of GSH-Ni NCs prepared in example 1 of the present invention applied to thiram detection;
FIG. 6 is a graph showing the results of a selectivity experiment in which GSH-Ni NCs prepared in example 1 of the present invention were applied to detection of thiram.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are not indicated by manufacturers and are commercially available.
Some embodiments of the present invention provide a fluorescent metal nanocluster (GSH-Ni NCs) including a nickel metal nanostructure and a glutathione ligand attached to the nickel metal nanostructure by a chemical bond.
Specifically, the fluorescent metal nanocluster has a particle size of 2 to 9nm, an average particle size of about 5nm, a maximum excitation wavelength of 380nm and a maximum emission wavelength of 445nm, and has optical properties of aggregation-induced fluorescence enhancement.
The fluorescent metal nanocluster formed by attaching the glutathione ligand to the nickel metal nanostructure through an S-Ni chemical bond can be used as a fluorescent probe to rapidly, sensitively and specifically identify DTC organic compounds. The method overcomes the defects of long detection time consumption, complicated steps and high cost of the existing pesticide residue detection method.
Some embodiments of the present invention also provide a method for preparing the above fluorescent metal nanocluster, which includes: and (3) stably synthesizing the metal nickel ions and the glutathione ligand into the fluorescent metal nanocluster.
Specifically, in some embodiments, the method for preparing the fluorescent metal nanoclusters is: carrying out hydrothermal reaction on nickel salt and glutathione to form the fluorescent metal nanocluster.
Further, in some embodiments, the nickel salt includes but is not limited to nickel chloride, nickel sulfate, nickel nitrate, and the like, and the molar ratio of the nickel salt to the glutathione is 1. In some embodiments, the method for preparing the fluorescent metal nanoclusters includes: with NiCl 2 GSH is used as a stabilizer and ascorbic acid is used as a reducing agent as raw materials, and the metal nanoclusters are subjected to fluorescence through a one-pot method.
In some embodiments, the method for preparing the fluorescent metal nanocluster specifically includes:
s1, adjusting the pH of the mixed solution of the nickel salt and the glutathione to 8-12, preferably 10, and then adding a reducing agent solution into the mixed solution.
In some embodiments, the aqueous solution of nickel salt and the aqueous solution of glutathione are prepared separately and then mixed well, wherein the concentration of the aqueous solution of nickel salt is 5-30mM, preferably 10-25 mM, more preferably 20mM, and the concentration of the aqueous solution of glutathione is 5-90mM, preferably 20-70 mM, more preferably 50mM.
In some embodiments, the thorough mixing is ultrasonic dissolution for 2-10 min, such as 2min,3min,4min,5min,6min,7min,8min,9min or 10min, preferably 5min.
In some embodiments, the reducing agent is used in a molar ratio of reducing agent to nickel salt of 1. In some embodiments, the reducing agent is Ascorbic Acid (AA) and the concentration of the ascorbic acid solution may be 112mM.
S2, carrying out hydrothermal reaction on the mixed solution added with the reducing agent solution at the temperature of 80-100 ℃ for 12-48 h.
Wherein the temperature of the hydrothermal reaction may be 80 ℃, 82 ℃, 85 ℃, 87 ℃, 88 ℃,90 ℃, 92 ℃, 95 ℃, 97 ℃ or 100 ℃, preferably 85 to 95 ℃, more preferably 90 ℃. The hydrothermal reaction time may be 12h, 14h, 16h, 18h, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 28h, 30h, 32h, 34h, 36h, 40h, 42h, 44h, 46h or 48h, etc., preferably 18 to 36h, more preferably 24h.
By selecting proper reaction temperature and reaction time, glutathione and nickel salt can be fully reacted, and the generated fluorescent metal nanocluster has good morphology.
In some embodiments, the method for preparing the fluorescent metal nanocluster specifically includes:
s1, preparing NiCl with the concentration of 5-30mM 2 0.5-10 mL of aqueous solution.
S2, preparing 0.5-10 mL of Glutathione (GSH) aqueous solution with the concentration of 5-90mM.
S3, mixing NiCl 2 Adding the solution into glutathione water solution to ensure that NiCl in the solution is dissolved 2 And the molar ratio of the glutathione to the water is 1-1.
And S4, adding NaOH into the mixed solution to adjust the pH value of the solution to 8-12, preferably 10, and fully mixing.
S5, adding 0.5-10 mL of 112mM Ascorbic Acid (AA) into the mixed solution after adjusting the pH, and fully and uniformly mixing.
S6, carrying out a hydrothermal reaction on the mixed solution in a water bath at the temperature of 80-100 ℃; the time of the hydrothermal reaction is 12 to 48 hours.
It should be noted that the mixed solution obtained after the hydrothermal reaction can be directly used for detection, or can be freeze-dried and then refrigerated for use, and then taken out, so that the fluorescent probe can be effectively prevented from deteriorating by refrigerating, the service life of the probe can be prolonged, and the accuracy of the detection result can be ensured. Wherein the refrigeration temperature is 4 ℃.
Some embodiments of the present invention also provide a fluorescent solution comprising the above fluorescent metal nanoclusters and a solvent, preferably, the solvent contains ethylene glycol. The solution obtained by mixing the fluorescent metal nanocluster and the solvent has higher glycol content and stronger fluorescence intensity, so that the fluorescent metal nanocluster has an aggregation-induced fluorescence enhancement phenomenon in the mixed solution of glycol and water.
In order to make the fluorescence solution have better fluorescence imaging effect, in some embodiments, the volume content of the glycol in the solvent is greater than or equal to 30%, and preferably the volume content of the glycol is greater than or equal to 90%.
Some embodiments of the present invention also provide the use of the above-described fluorescent metal nanoclusters in the detection of dithiocarbamate compounds. Preferably, the dithiocarbamate compound is an organic pesticide residue. Specifically, the method can be used for detecting organic pesticide residues in an environmental water sample or a traditional Chinese medicine sample.
The present inventors have discovered that DTC compounds can quench the fluorescence of the nanoclusters prepared by embodiments of the present invention. In some embodiments, the DTC compound may be any one of thiram, ferbam, ziram, propineb, and metiram. Taking DTC pesticide residue thiram as an example, concentration gradient detection on the thiram shows that the nickel nanocluster protected by the glutathione has specific selectivity and high sensitivity on the thiram. When the dithiocarbamate compound is thiram, the linear range for detecting the thiram is 0.5-75 mu M, and the detection limit is 130.7nM.
Some embodiments of the present invention also provide a method for detecting a dithiocarbamate compound, which detects the dithiocarbamate compound using the fluorescent metal nanocluster as a fluorescent probe.
Specifically, in some embodiments, the fluorescent probe is mixed with the sample to be detected, and then fluorescence detection is performed, preferably, the excitation wavelength for fluorescence detection is 370-390 nm, preferably 380nm. Dissolving the sample to be detected in an aqueous solution of ethylene glycol, and then neutralizing Cu 2+ Incubating, and adding fluorescent probe for detection, preferably, the volume content of ethylene glycol in the aqueous solution of ethylene glycol is 55-65%, more preferably 60%, and Cu in the incubated mixed solution 2 The concentration of (2) is 220 to 280. Mu.M, preferably 250. Mu.M, and the incubation time is 18 to 22min, preferably 20min.
Furthermore, for DTC detection, a fluorescence spectrophotometry method is adopted, taking thiram as an example, a solution to be detected containing thiram is firstly added into a fluorescent metal nanocluster system, and then, under the condition that the wavelength of excitation light is 380nm, the peak height of emission light of the detection solution at 445nm is detected, and 1mL is preferred as a detection standard system. Wherein, the solution to be detected containing thiram is 100 mu L and Cu (NO) 3 ) 2 After 100 mu L of water is dissolved in a 1.5mL centrifuge tube and incubated for 20 minutes at normal temperature, the fluorescent metal nanoclusters are added, the fluorescence spectrum of GSH-Ni NCs is tested under the excitation of 380nm wavelength light, and the fluorescence intensity of an emission peak at the wavelength of 445nm is detected. In the fluorescent metal nanocluster system, 100 mu L of GSH-Ni NCs is added into a solution to be detected, and water and ethylene glycol are added to make up to 1mL.
The features and properties of the present invention are described in further detail below with reference to examples.
Drugs and reagents: tetramethylthiuram disulfide (thiram), nickel (II) chloride hexahydrate (NiCl) 2 ·6H 2 O), ascorbic Acid (AA), copper (II) nitrate trihydrate Cu (NO) 3 ) 2 ·3H 2 O and Ethylene Glycol (EG) were purchased from Aladdin Reagent co.ltd. (shanghai, china). Glutathione (A)GSH) from J&K Scientific ltd. (beijing, china). All chemicals were at least analytically pure and no further purification was required before use. The experimental water was double distilled water.
Example 1
The preparation method of the fluorescent metal nanocluster provided by the embodiment comprises the following steps:
10mL of NiCl 2 The aqueous solution (20 mM) and 10mL of the aqueous GSH solution (50 mM) were added to 70mL of ultrapure water, mixed thoroughly, and sonicated at room temperature for 5 minutes. 1M aqueous NaOH solution was added dropwise to bring the pH of the above mixture to 10, and then 10mL of aqueous ascorbic acid solution (112 mM) was added dropwise. Then heating and stirring the mixture at 90 ℃ for reaction for 24 hours to obtain light yellow nickel nano-cluster aqueous solution.
For further purification, the reaction mixture was lyophilized, and the resulting solid was washed 3 times with ethanol and dried by nitrogen blow to obtain a dark yellow solid, i.e., fluorescent metal nanoclusters (GSH-Ni NCs). The final product was stored in a refrigerator at 4 ℃ until use.
Structural characterization of GSH-Ni NCs:
the ultraviolet-visible absorption spectrum, the fluorescence excitation spectrum and the fluorescence emission spectrum of the GSH-Ni NCs prepared in the embodiment are shown in FIG. 1, and as can be seen from FIG. 1, the GSH-Ni NCs prepared in the embodiment have a distinct shoulder at 300nm, but the raw material GSH has no maximum absorption at this position, which proves that the GSH-Ni NCs prepared in the embodiment and the GSH are not the same substance per se. And the maximum excitation wavelength of the nano-cluster is 380nm, and the maximum emission wavelength is 445nm.
To further investigate the chemical structure of GSH-Ni NCs, the infrared spectra (FT-IR) of the nanoclusters and their raw GSH were measured and compared as shown in FIG. 2, with the most significant difference between the two spectra being that the GSH was 2525cm -1 The characteristic peak of the-S-H stretching vibration disappears in GSH-Ni NCs. This phenomenon indicates that during the formation of nickel nanoclusters, the S-H bond of GSH is broken and the glutathione ligand is attached to the nickel metal nanostructure through S-Ni chemical bonds, forming GSH-Ni NCs.
Further, the GSH — Ni NCs of this example was observed by transmission electron microscopy, and as shown in fig. 3, it exhibited spherical particles with a diameter of about 5nm.
Example 2
The preparation method of the fluorescent metal nanocluster provided by the embodiment comprises the following steps:
10mL of NiCl 2 The aqueous solution (20 mM) and 10mL of the GSH aqueous solution (90 mM) were added to 70mL of ultrapure water, mixed thoroughly, and sonicated at room temperature for 10 minutes. 1M aqueous NaOH solution was added dropwise to bring the pH of the mixture to 9, and then 10mL of aqueous ascorbic acid solution (112 mM) was added dropwise. Then heating and stirring the mixture at 90 ℃ to react for 24 hours to obtain light yellow nickel nano-cluster aqueous solution.
For further purification, the reaction mixture was lyophilized, and the resulting solid was washed 3 times with ethanol and dried by nitrogen blow to obtain a dark yellow solid, i.e., fluorescent metal nanoclusters (GSH-Ni NCs). The final product was stored in a refrigerator at 4 ℃ until use.
Example 3
The preparation method of the fluorescent metal nanocluster provided by the embodiment comprises the following steps:
10mL of NiCl 2 The aqueous solution (10 mM) and 10mL of the GSH aqueous solution (25 mM) were added to 70mL of ultrapure water, mixed thoroughly, and sonicated for 5 minutes at room temperature. 1M aqueous NaOH solution was added dropwise to bring the pH of the above mixture to 8, and then 5mL of aqueous ascorbic acid solution (112 mM) was added dropwise. Then heating and stirring the mixture at 90 ℃ for reaction for 24 hours to obtain light yellow nickel nano-cluster aqueous solution. The final product was stored in a refrigerator at 4 ℃ until use.
Example 4
The preparation method of the fluorescent metal nanocluster provided by the embodiment comprises the following steps:
0.5mL of NiCl was added 2 The aqueous solution (5 mM) and 0.5mL of the aqueous GSH solution (5 mM) were added to 3.5mL of ultrapure water, mixed thoroughly, and sonicated at room temperature for 5 minutes. 1M aqueous NaOH solution was added dropwise to bring the pH of the mixture to 10, and then 0.5mL of aqueous ascorbic acid solution (112 mM) was added dropwise. Then heating and stirring the mixture at 80 ℃ to react for 20 hours to obtain light yellow nickel nano-cluster aqueous solution. The final product was stored in a refrigerator at 4 ℃ until use.
Test example 1
GSH-Ni NCs prepared in the same amount as in example 1 were dissolved in ethylene glycol/water solutions (0%, 10%,30%,50%,70%,90% respectively) of different proportions, and fluorescence spectra of the GSH-Ni NCs were measured under excitation of light having a wavelength of 380nm, and fluorescence intensity of an emission peak at a wavelength of 445nm was detected. As shown in FIG. 4, it is understood from FIG. 4 that the fluorescence intensity of GSH-Ni NCs increases with the increase in the proportion of ethylene glycol, indicating that GSH-Ni NCs have a solvent-induced aggregation-induced fluorescence enhancement effect (AIEE).
Test example 2
Mixing 100 μ L of thiram glycol solution with 100 μ L of Cu (NO) 3 ) 2 The aqueous solution (250. Mu.M) was mixed well in a 1.5mL centrifuge tube, and the effect of different concentrations of Thiram (Thiram) on the fluorescence signal of the GSH-Ni NCs probe was examined (final concentrations of 0, 0.5, 1, 2.5, 5, 10, 25, 50, 75, 100, 150. Mu.M). Incubation at room temperature for 20min to form thiram-Cu 2+ After complexing, the mixture was diluted with 500. Mu.L of ethylene glycol and 200. Mu.L of double distilled water and mixed well. Then, 100. Mu.L of GSH-Ni NCs prepared in example 1 was added to the mixture before the fluorometric measurement was performed. Under the excitation of 380nm wavelength light, the fluorescence spectrum of GSH-Ni NCs is tested, and the emission peak fluorescence intensity at the 445nm wavelength is detected. The fluorescence signal of the sample after the addition of thiram was measured and the fluorescence intensity at the position of the maximum emission peak was recorded as I 0 And I is GSH-Ni NCs per se and added thiram-Cu respectively 2+ Fluorescence intensity of the complex. The experiment was repeated 3 times and the results averaged. Wherein the solvent ethylene glycol solution EG/H2O of the thiram ethylene glycol solution is 60 percent, and Cu 2+ The concentration was 250. Mu.M. The quenching effect reached equilibrium after 20 minutes of incubation time.
The response of GSH-Ni NCs to different concentrations of thiram was studied by fluorescence emission spectroscopy. As shown in FIG. 5, it is understood from FIG. 5 that the degree of fluorescence quenching of GSH-Ni NCs increases with the increase of concentration of thiram, and the relative fluorescence intensity linear detection curve is I 0 /I＝0.03893[Thiram]+1.022, coefficient of correlation R 2 =0.9901, the linear range of the constructed detection thiram is 0.5-75 μ M, and the detection limit is 130.7nM. The results show that GSH-Ni prepared by the embodiment of the inventionNCs (NCs), namely the nickel nanocluster fluorescent probe, can be used for analyzing and detecting the content of pesticide residues in an actual sample.
Test example 3
To evaluate the specificity of the probe for thiram in potential competitors, a series of pesticides with different structural types including acephate, chlorpyrifos, systemic phosphorus, paraquat, methyl parathion, vodka and profenofos and common ions including Na in environmental samples were tested under the same conditions respectively + ,Cl - ,SO 4 2- ,K + ,Mg 2+ ,Zn 2+ ,Al 3+ And Pb 2+ . The specific operation method was the detection method in test example 2. The results are shown in fig. 6, and it can be seen from fig. 6 that only thiram causes fluorescence quenching, and other pesticides and ions have no significant influence on the fluorescence intensity. The excellent selectivity is attributable to Cu 2+ Specific complexation with dithiocarbamate structure. The results show that the method can selectively detect the DTC compounds, has strong anti-interference capability and can be used for detecting complex samples.
Example 5
In order to more clearly illustrate the application scheme of the embodiment of the invention and prove the practicability of GSH-Ni NCs as a probe for detecting thiram, the detection process of two traditional Chinese medicine samples is described in detail below. GSH-Ni NCs were prepared as described in example 1.
1. Sample source
Semen Nelumbinis and Coicis semen are purchased from Macau drugstore.
2. Detection process
Respectively taking 3.0g of lotus seed and coix seed samples, mixing with 6mL of acetonitrile, and carrying out ultrasonic extraction on ice bath for 10 minutes. The extract was dried by nitrogen purge and then re-dissolved in 1mL of ethylene glycol for use.
The detection system is 1mL, wherein 100 mu L of the detection system is the medicinal material extracting solution to be detected, the detection method refers to the test example 2, and the test result is substituted into the standard curve drawn by the test example 2 for calculation.
And (3) detecting the processed medicinal material sample according to the method, and independently repeating the experiment for 3 times. Thiram was not detected in all three samples.
3. Detecting the recovery rate of the added standard:
and (3) respectively carrying out recovery rate detection of thiram in the standard sample on the two samples under the thiram concentrations of 5 mu M and 50 mu M, referring to the test example 2 by the detection method, substituting the test result into a standard curve drawn by the test example 2 for calculation, and determining the recovery rate, wherein the detection results are shown in the table 1.
TABLE 1 results of recovery of thiram in lotus seed and coix seed samples
The results show that the method has good application effect in practical samples. Verifies GSH-Ni NC S The fluorescent probe has high reliability and practicability as a detection method of thiram.
In summary, first, the present invention utilizes glutathione and NiCl 2 The fluorescent metal nanoclusters (GSH-Ni NCs) are successfully prepared by reaction and can be used as fluorescent probes, and the preparation method is simple and convenient to operate, easy to operate, low in cost, green and mild. Secondly, the fluorescent metal nanoclusters are high in stability, have the property of aggregation-induced fluorescence enhancement, and do not need any modification step on the material. Again, DTC-Cu can be utilized 2+ The interaction between the complex and the glutathione nickel nanocluster generates the fluorescence quenching phenomenon of the nickel nanocluster, and the fluorescence quenching phenomenon can be used for detecting DTC pesticide residues. Finally, the determination method provided by the embodiment of the invention has the advantages of good selectivity, high sensitivity, wide detection range and simple and convenient operation, can be widely applied to actual sample detection, and has important significance for monitoring the quality market of crop products.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (33)
1. A fluorescent metal nanocluster comprising a nickel metal nanostructure and a glutathione ligand attached to the nickel metal nanostructure by a chemical bond;
the particle size of the fluorescent metal nanocluster is 2-9 nm.
2. The fluorescent metal nanoclusters according to claim 1, wherein the fluorescent metal nanoclusters have a maximum excitation wavelength of 380nm and a maximum emission wavelength of 445nm.
3. A method for preparing the fluorescent metal nanoclusters of claim 1 or 2, comprising:
and adjusting the pH value of the mixed solution of the nickel salt and the glutathione to 8-12, then adding a reducing agent solution into the mixed solution, and carrying out hydrothermal reaction by using the nickel salt and the glutathione to form the fluorescent metal nanocluster.
4. The method according to claim 3, wherein the nickel salt is nickel chloride, nickel sulfate, or nickel nitrate.
5. The method according to claim 3, wherein the molar ratio of the nickel salt to the glutathione is 1.
6. The production method according to claim 5, characterized in that the mixed solution of the nickel salt and the glutathione is adjusted to pH 10.
7. The method according to claim 5, wherein the molar ratio of the reducing agent to the nickel salt is 1.
8. The method according to claim 7, wherein the molar ratio of the reducing agent to the nickel salt is 1.
9. The method according to claim 7, wherein the reducing agent is ascorbic acid.
10. The method according to claim 3, wherein the aqueous solution of nickel salt and the aqueous solution of glutathione are prepared separately and then mixed well, and the concentration of the aqueous solution of nickel salt is 5 to 30mM and the concentration of the aqueous solution of glutathione is 5 to 90mM.
11. The method according to claim 10, wherein the concentration of the nickel salt aqueous solution is 10 to 25mM, and the concentration of the glutathione aqueous solution is 20 to 70mM.
12. The method according to claim 10, wherein the concentration of the aqueous nickel salt solution is 20mM and the concentration of the aqueous glutathione solution is 50mM.
13. The preparation method according to claim 10, wherein the sufficient mixing is ultrasonic dissolution, and the ultrasonic time is 2-10 min.
14. The method of claim 13, wherein the sonication time is 5min.
15. The preparation method according to claim 3, wherein the temperature of the hydrothermal reaction is 80-100 ℃ and the time of the hydrothermal reaction is 12-48 hours.
16. The preparation method according to claim 15, wherein the temperature of the hydrothermal reaction is 85 to 95 ℃ and the time of the hydrothermal reaction is 18 to 36 hours.
17. The method according to claim 16, wherein the temperature of the hydrothermal reaction is 90 ℃ and the time of the hydrothermal reaction is 24 hours.
18. A fluorescent solution comprising the fluorescent metal nanoclusters of claim 1 or 2 and a solvent.
19. A fluorescent solution according to claim 18, characterized in that the solvent contains an alcohol.
20. A fluorescent solution according to claim 19, wherein the alcohol is ethylene glycol, methanol, ethanol or propanol.
21. A fluorescent solution according to claim 20, wherein the alcohol is ethylene glycol.
22. A fluorescent solution according to claim 20, wherein the solvent has an alcohol content of greater than or equal to 30% by volume.
23. A fluorescent solution according to claim 22, wherein the alcohol is present in an amount greater than or equal to 90% by volume.
24. Use of the fluorescent metal nanoclusters according to claim 1 or 2 for detecting dithiocarbamate compounds.
25. The use according to claim 24, wherein the dithiocarbamate compound is any one of thiram, ferbam, ziram, propineb and metiram.
26. The use according to claim 24, wherein when the dithiocarbamate compound is thiram, the linear range for detecting thiram is 0.5 μ M to 75 μ M, and the detection limit is 130.7nM.
27. A method for detecting a dithiocarbamate compound, which comprises detecting the dithiocarbamate compound using the fluorescent metal nanocluster according to claim 1 or 2 as a fluorescent probe.
28. The assay of claim 27 wherein the fluorescent probe is mixed with a sample to be assayed prior to fluorescence detection.
29. The detection method according to claim 28, wherein the fluorescence detection uses an excitation wavelength of 370 to 390nm.
30. The detection method according to claim 29, wherein the fluorescence detection uses an excitation wavelength of 380nm.
31. The assay of claim 28 wherein the sample to be assayed is dissolved in an aqueous solution of ethylene glycol and then mixed with Cu 2+ And (5) incubating, and then adding the fluorescent probe for detection.
32. The detection method according to claim 31, wherein the ethylene glycol aqueous solution contains 55 to 65% by volume of ethylene glycol, and the incubated mixed solution contains Cu 2 The concentration of (A) is 220-280 mu M, and the incubation time is 18-22 min.
33. The detection method according to claim 32, wherein the ethylene glycol is 60% by volume, and the mixed solution is incubated to contain Cu 2 The concentration of (3) was 250. Mu.M, and the incubation time was 20min.
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