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CN-121988747-A - Synthesis method of gold nanoclusters and application of gold nanoclusters in food pigment detection

CN121988747ACN 121988747 ACN121988747 ACN 121988747ACN-121988747-A

Abstract

The invention relates to the technical field of nano materials, in particular to a synthesis method of gold nanoclusters and application thereof in food pigment detection, which takes natural plant protein ginger protease containing sulfhydryl and reducing amino acid as a special template and comprises the following steps: preparing an enzyme solution and a chloroauric acid solution, mixing and stirring according to a proportion to form a colloid, adding NaOH to adjust pH to enable a protein structure to be unfolded, carrying out microwave treatment after constant volume mixing, cooling and preserving in a dark place. The invention innovatively selects ginger protease as a template, adapts microwave synthesis, shortens the synthesis period, improves the product performance, has strong specificity of a detection system, good anti-interference performance, mild reaction conditions, simple and convenient operation, is suitable for rapid detection of target pigments in various foods, and has high application value.

Inventors

  • LIU CAN
  • WANG ZHENG
  • FAN PENGFEI
  • HU CONGCONG
  • LI JUNHONG

Assignees

  • 常州市疾病预防控制中心

Dates

Publication Date
20260508
Application Date
20260130

Claims (10)

  1. 1. The synthesis method of the gold nanocluster is characterized by comprising the following steps of: S1, selecting ginger protease raw material, dissolving the ginger protease raw material by PBS buffer solution to prepare 80mg/ml solution; S2, dissolving analytically pure chloroauric acid in ultrapure water, and fixing the volume to prepare chloroauric acid solution with the concentration of 5 mmol/L; S3, slowly dripping the chloroauric acid solution of S2 into the ginger protease solution of S1 according to the volume ratio of the chloroauric acid to the ginger protease of 1.6:1.8, and stirring for 10min at 25 ℃ at 300r/min to form a white colloid system; S4, dropwise adding NaOH solution with the concentration of 0.4mol/L and the purity of more than or equal to 98 percent into the white colloid system of the S3, stirring while dropwise adding, adjusting the pH value of the system to 12.0+/-0.2, and recovering the system to be in a uniform solution state; s5, supplementing the solution system of the S4 to 5mL by using ultrapure water, and continuously stirring for 2min at 300 r/min; S6, placing the system of the S5 in a household microwave oven, performing microwave treatment by adopting medium and low fire with rated power of 40% -50%, wherein the treatment time is 50+/-5 seconds, heating the system to 55 ℃ -65 ℃ under the microwave field, reducing Au 3+ into 0-valence Au atoms, regularly stacking and gathering to form gold nanoclusters, and placing the product in a brown sealed container after the reaction is finished, and storing in a 4 ℃ environment in a dark place to obtain the GP-AuNCs.
  2. 2. The method for synthesizing gold nanoclusters according to claim 1, wherein in the preparation process of the ginger protease solution in S1, the dissolution temperature is controlled to be 20 ℃ to 25 ℃, and impurities are removed by filtration through a 0.22 μm filter membrane after the solution is prepared.
  3. 3. The method for synthesizing gold nanoclusters according to claim 1, wherein a magnetic stirrer is used in the stirring process in the step S3, the fluctuation range of the rotation speed of a stirring rod is not more than +/-10 r/min, and the speed of dropwise adding the chloroauric acid solution is 0.5-1 mL/min.
  4. 4. The method for synthesizing gold nanoclusters according to claim 1, wherein the dropping rate of the NaOH solution in S4 is 0.2mL/min, and the pH is adjusted by monitoring in real time using a pH meter having an accuracy of 0.01.
  5. 5. The method for synthesizing gold nanoclusters according to claim 1, wherein the rated power of a microwave oven for microwave treatment in S6 is 700w to 1000w, the microwave frequency is 2450MHz, and the intermittent irradiation mode of microwaves is adopted in the treatment process, and the irradiation is stopped for 1 second for 5 seconds.
  6. 6. The method for synthesizing gold nanoclusters according to claim 1, wherein the activity of ginger protease in S1 is 400U/mg to 600U/mg, the particle size of GP-AuNCs is 2.00±0.35nm, and the lattice spacing is 0.18nm.
  7. 7. Use of gold nanoclusters according to claim 1 in food coloring brilliant blue detection, characterized by comprising the steps of: S1, preparing PBS buffer solution with the concentration of 0.05mol/L, regulating the pH value to 6.5+/-0.1 by using 0.1mol/L HCl or NaOH solution, and performing high-pressure sterilization for later use; s2, mixing GP-AuNCs with PBS buffer solution of S1 according to a volume ratio of 1:8 to prepare fluorescence detection mother solution, wherein the mother solution can be stably stored for 7 days under the light-shielding condition at 4 ℃; S3, 1mL of fluorescence detection mother liquor is taken and placed in a cuvette, 0.1mL of food sample extracting solution to be detected is added, and the mixture is kept stand at the room temperature of 25 ℃ for reaction for 10+/-1 min; s4, measuring the fluorescence intensity F of the reacted system at 650nm by using a fluorescence spectrometer with 380nm as excitation wavelength, simultaneously measuring the blank fluorescence intensity F0 of 1mL of fluorescence detection mother liquor mixed with 0.1mL of ultrapure water, and calculating the fluorescence quenching degree delta F=F0-F; S5, substituting the delta F value in the step S4 according to the relation between the fluorescence quenching degree and the pigment concentration, and calculating to obtain the concentration of the pigment in the sample to be detected.
  8. 8. The application of gold nanoclusters in food pigment brilliant blue detection according to claim 7, wherein the preparation method of the food sample extract to be detected in S3 comprises the steps of taking a food sample, adding 60% ethanol solution with volume fraction, performing ultrasonic extraction at 30 ℃ for 20min, centrifuging, taking supernatant, and filtering with a 0.45 μm filter membrane for later use.
  9. 9. The application of the gold nanoclusters in food coloring brilliant blue detection according to claim 7, wherein the detection linear range in S5 is 0.25 μg/mL-2.5 μg/mL, and the detection limit is 0.08 μg/mL.
  10. 10. The application of gold nanoclusters in food coloring brilliant blue detection according to claim 7, wherein the application is suitable for rapid quantitative detection of brilliant blue in beverages, cakes and confectionery, and the detection period of a single sample is not more than 20min.

Description

Synthesis method of gold nanoclusters and application of gold nanoclusters in food pigment detection Technical Field The invention relates to the technical field of nano materials, in particular to a synthesis method of gold nanoclusters and application of the gold nanoclusters in food pigment detection. Background Gold nanoclusters are novel nanomaterial consisting of several to tens of gold atoms, and have a size of about 2nm, close to the fermi wavelength of gold atoms, and have both the natural enzyme-like catalytic property and unique photoluminescence properties of gold nanoparticles, so that the gold nanoclusters have wide application prospects in the fields of fluorescence detection, biosensing, catalysis and the like. In the synthesis process, the selection of the template is crucial, so that the aggregation of gold atoms can be effectively prevented to form large-particle-size nano particles, the structure, fluorescence performance and function expansion of gold nanoclusters can be directly determined, the current commonly used templates comprise proteins, amino acids, thiol substances, polymer macromolecules and the like, and the fluorescence colors and the functional characteristics of the gold nanoclusters synthesized by different templates are obviously different. However, existing gold nanocluster synthesis techniques still face a number of bottlenecks. The traditional template method is mostly prepared by adopting a water phase room temperature stirring mode, has the problems of long synthesis period, low efficiency, low fluorescence quantum yield and the like, and severely limits the large-scale production and practical application of the template method. Although the microwave-assisted synthesis method is proved to greatly shorten the reaction time, improve the quantum yield and prevent the fluorescence stability of the product from being affected, the method has extremely high selectivity on templates, only a few thiol-containing amino acids or thiol-containing amino acid proteins (such as BSA, GSH and the like) can be adapted, so that the types of templates which can be used for microwave synthesis are scarce, and the diversified development and application scene expansion of gold nanocluster synthesis are restricted. Meanwhile, the novel template in the prior art is slowly explored, relevant research documents are fresh, and the requirements of rich gold nanocluster synthesis theory and expansion of application fields are difficult to meet. In the detection field, food pigment is used as a common food additive, and the content exceeding the standard can harm the health of human bodies, so that the establishment of a rapid and accurate detection method has important practical significance. The traditional food pigment detection method has the defects of complex operation, long detection period, weak anti-interference capability and the like, and the gold nanocluster has great potential in pigment detection by virtue of excellent fluorescence performance, but the existing detection system based on the gold nanocluster still has the problems of poor suitability of buffer conditions, harsh reaction conditions, insufficient specificity and the like, and is difficult to meet the actual requirements of rapid detection of pigments in complex food matrixes. In summary, development of a novel template and an efficient synthesis method are needed, the problems of time consumption and template limitation of gold nanocluster synthesis are solved, and a detection system with excellent performance is constructed so as to promote practical application of gold nanoclusters in food pigment detection. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides a synthesis method of gold nanoclusters and application thereof in food pigment detection. (II) technical scheme A synthesis method of gold nanoclusters comprises the following steps: S1, selecting ginger protease raw material, dissolving the ginger protease raw material by PBS buffer solution to prepare 80mg/ml solution; S2, dissolving analytically pure chloroauric acid in ultrapure water, and fixing the volume to prepare chloroauric acid solution with the concentration of 5 mmol/L; S3, slowly dripping the chloroauric acid solution of S2 into the ginger protease solution of S1 according to the volume ratio of the chloroauric acid to the ginger protease of 1.6:1.8, and stirring for 10min at 25 ℃ at 300r/min to form a white colloid system; S4, dropwise adding NaOH solution with the concentration of 0.4mol/L and the purity of more than or equal to 98 percent into the white colloid system of the S3, stirring while dropwise adding, adjusting the pH value of the system to 12.0+/-0.2, and recovering the system to be in a uniform solution state; s5, supplementing the solution system of the S4 to 5mL by using ultrapure water, and continuously stirring for 2min at 300 r/min; S6, placing the syst