Amino acid-based molecularly imprinted polymer / quantum composite material, preparation method and application thereof

Abstract

The application belongs to the field of molecular imprinting polymer separation materials, and provides an amino acid-based molecular imprinting polymer / quantum composite material, a preparation method and application thereof, and comprises the following steps: mixing an inorganic quantum dot material dispersion liquid, two kinds of amino acid template molecules, 3-aminopropyl triethoxysilane, tetraethyl orthosilicate and a stabilizer, then adding ammonia water and deionized water, uniformly dispersing, and reacting at room temperature to obtain a polymerization product; and after elution and post-treatment of the polymerization product, the template molecules are removed to obtain the amino acid-based molecular imprinting polymer / quantum composite material. The composite material can be applied to the separation and identification of various amino acids, and all have high separation and identification performance, so that one material can effectively separate and identify various target molecules, and the concentration of the amino acid molecules can be quantitatively analyzed.

Description

An amino acid-based molecularly imprinted polymer / quantum composite material, its preparation method, and its application. Technical Field

[0001] This invention belongs to the field of molecularly imprinted polymer separation materials, specifically relating to an amino acid-based molecularly imprinted polymer / quantum composite material, its preparation method, and its application. Background Technology

[0002] L-amino acids are essential components of certain enzymes and active protein molecules in the human body and are widely used in food, medicine, and cosmetics. In 2002, researchers also discovered D-amino acids in animals and humans. Further studies revealed a close correlation between D-amino acids and certain human diseases, such as Alzheimer's disease, depression, and schizophrenia. Amino acids are intermediate raw materials in the synthesis of many drugs. To ensure the formation of a single enantiomer, D-amino acids or L-amino acids are typically chosen when synthesizing drugs using amino acids. However, most non-natural amino acids exist in racemic form. Therefore, establishing an efficient method for the separation and analysis of D- and L-amino acids is of great significance.

[0003] Molecularly imprinted polymers are important materials for separating and purifying certain substances. A molecularly imprinted polymer is a polymer in which the molecule to be separated or identified is used as a template and polymerized with a monomer. After the template molecule is separated, the corresponding hole of the template molecule is imprinted in the polymer, thereby giving the polymer the function of separating and recognizing the template molecule.

[0004] Inorganic quantum dots possess fluorescence recognition properties. Combining them with molecularly imprinted polymers to form quantum composite materials can effectively improve the ability to recognize and separate target molecules.

[0005] Traditional molecularly imprinted polymers (MIPs) for separating or recognizing target molecules use the separated molecule as a template for preparing the MIP, which is then used to recognize the target molecule. Most often, a single target molecule is used as the template molecule for MIP preparation, which is then used for target molecule recognition. For example, Chinese literature (Liu Luying, et al. Specific adsorption and detection of riboflavin using a molecularly imprinted carbon quantum dot fluorescent sensor, Journal of Analytical Science, 2002, Vol. 38, No. 4, pp. 503-507) describes the specific adsorption and detection of riboflavin using a molecularly imprinted carbon quantum dot fluorescent sensor; while Chinese literature (Zhao Fei, et al. Preparation of quantum dot-imprinted polymers and their application in the determination of L-arginine, Contemporary Chemical Research, 2023, No. 11, pp. 86-88) uses L-arginine as a template to prepare a quantum dot / imprinted polymer for the determination of L-arginine. Examples of preparing molecularly imprinted polymers using multiple molecules as templates exist, such as Chinese patent CN113209948A, "A method for preparing and applying a multi-template molecularly imprinted composite material"; and CN112007621A, "A method for preparing and applying a multi-template molecularly imprinted magnetic composite material for tetracycline antibiotics." However, all separated molecules must be used as template molecules to achieve multi-molecule recognition. As described above, the detection method requires separated molecules as templates, which, while specific, lacks universality and is costly, making widespread application difficult. Summary of the Invention

[0006] To address the problems of existing technologies, this invention provides a molecularly imprinted polymer / quantum composite material with two amino acids as templates and a preparation method thereof. This material is applied to the separation and recognition of up to seven amino acids, all of which exhibit high separation and recognition performance, achieving the goal of effectively separating and recognizing multiple target molecules with a single material.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material, comprising the following steps:

[0009] (1) The inorganic quantum dot material was uniformly dispersed in anhydrous ethanol to obtain an inorganic quantum dot material dispersion;

[0010] (2) Take the inorganic quantum dot material dispersion from step (1), add two amino acids as amino acid template molecules, and continue to add 3-aminopropyltriethoxysilane, tetraethyl orthosilicate and stabilizer. Then add ammonia and deionized water and mix evenly. React at room temperature in the dark and collect the polymerization product by centrifugation.

[0011] (3) The polymerization product from step (2) is eluted and post-treated to remove the template molecules and obtain the amino acid-based molecularly imprinted polymer / quantum composite material.

[0012] For ease of use, the composite material is ground and crushed into particles with an average particle size of 10-30 micrometers.

[0013] Preferably, the inorganic quantum dot material mentioned in step (1) is selected from any one of carbon quantum dots, graphene quantum dots, CdTe quantum dots or CdS quantum dots, and has a particle size of 4-10 nm.

[0014] Preferably, the uniform dispersion in step (1) is achieved by ultrasonic dispersion for 30-40 minutes.

[0015] Preferably, the two amino acids in step (2) are L-alanine and L-isoleucine, with a molar ratio of 1:1.

[0016] Preferably, the stabilizer mentioned in step (2) is any one of mercaptoacetic acid, 3-mercaptopropionic acid or cysteine.

[0017] Preferably, the mixing method in step (2) is ultrasonic dispersion for 20-30 minutes.

[0018] Preferably, the reaction time in step (2) is 24-30 hours.

[0019] Preferably, the elution and post-treatment steps in step (3) are as follows: the polymer product is loaded into a chromatography column, eluted with 5% ammonia solution until template molecules are not detected in the eluent, then washed three times with 100ml to 150ml of deionized water, filtered and dried, and finally vacuum dried at 60°C for 12h.

[0020] Preferably, in steps (1) and (2), the amounts of each component are as follows:

[0021] 1-2 parts of inorganic quantum dot material;

[0022] 2-3 parts of amino acid template molecules;

[0023] 20-30 parts of 3-aminopropyltriethoxysilane;

[0024] 0.5-1.5 parts of tetraethyl orthosilicate;

[0025] Stabilizer 1.5-3 parts;

[0026] The weight-to-volume ratio of inorganic quantum dot material to anhydrous ethanol is (1-2):(10-20) g / ml;

[0027] The volume ratio of anhydrous ethanol, ammonia, and deionized water is (10-20):(20-30):(40-80);

[0028] The ammonia content of the water is 28%.

[0029] The present invention also provides an amino acid-based molecularly imprinted polymer / quantum composite material prepared by the above method.

[0030] The present invention also provides the application of the above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material for the quantitative detection of natural and non-natural aliphatic amino acids, wherein the natural aliphatic amino acids include glycine, L-alanine, L-valine, L-leucine, and L-isoleucine, and the non-natural aliphatic amino acids include L-valine and L-leucine.

[0031] Preferably, the detection method in the application includes the following steps:

[0032] (1) The fluorescence of the amino acid-based molecularly imprinted polymer / quantum composite material was tested using a fluorescence spectrophotometer to obtain the maximum fluorescence emission wavelength of the composite material;

[0033] (2) Perform analysis and testing at the maximum fluorescence emission wavelength obtained in step (1):

[0034] 1) Take 0.1g of the amino acid-based molecularly imprinted polymer / quantum composite material and add it to a 5mL centrifuge tube. Disperse it in 2mL of distilled water to obtain a composite material dispersion. Take 9 portions of the composite material dispersion and add 5mL of a standard solution of a target amino acid with concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively to obtain a set of mixed solutions. Shake at 180rpm for 2h and measure the fluorescence value of the set of mixed solutions. Plot the obtained fluorescence value on the ordinate and the concentration of the standard solution of the target amino acid on the abscissa to obtain the working curve of the target amino acid. Take the upper and lower limits of the linear portion of the working curve as the working interval for quantitative detection of the target amino acid molecule.

[0035] 2) Take the composite material dispersion described in step 1), add the test amino acid solution of the target amino acid, shake at 180 rpm for 2 h to obtain the test mixed solution, measure the fluorescence value of the test mixed solution, and calculate the concentration of the test amino acid molecules in the test mixed solution according to the working curve;

[0036] 3) The detection limit of the amino acid molecule to be tested was determined by using the signal-to-noise ratio method, S / N = 3, where S is the signal intensity and N is the noise intensity.

[0037] The detection limit is the concentration of the analyte when the ratio of the fluorescence emission peak signal to the baseline noise is 3.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) Two amino acid template molecules are added during the synthesis of molecularly imprinted polymers. A single amino acid-based copolymer molecularly imprinted polymer can detect multiple target amino acids, thus improving detection efficiency.

[0040] (2) By screening different combinations of template molecules, this invention found that the molecularly imprinted polymer / quantum composite material based on amino acids obtained by combining L-alanine and L-isoleucine as templates has good detection effect on a variety of aliphatic amino acids, including natural amino acids and non-natural chiral amino acids, with detection limits below 3.5 nmol / L. Moreover, it can quantitatively detect the concentration of the amino acid to be tested within a certain range.

[0041] (3) The molecularly imprinted polymer used in this invention only needs to select two of the separated amino acids as templates to achieve the recognition of seven amino acids. It is not necessary to use all the separated amino acids as templates, which greatly reduces the cost and simplifies the separation process. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer with the description. However, the embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0043] Example 1

[0044] A method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material includes the following steps:

[0045] (1) Weigh 1 gram of carbon quantum dot material, add it to 10 ml of anhydrous ethanol and ultrasonically disperse it for 30-40 minutes to obtain an inorganic quantum dot material dispersion, and store it at 4°C in the dark.

[0046] (2) Take the inorganic quantum dot material dispersion from step (1), add 1 g of L-alanine and 1 g of L-isoleucine as template molecules, and continue to add 22 g of 3-aminopropyltriethoxysilane, 1 g of tetraethyl orthosilicate and 1.5 g of mercaptoacetic acid as stabilizer. Then add 20 ml of ammonia water (mass fraction of 28%) and 50 ml of deionized water, sonicate for 20-30 min, react at room temperature in the dark for 24 h, and collect the polymerization product by centrifugation.

[0047] (3) The polymerization product from step (2) is loaded into a chromatography column and eluted with 5% ammonia solution until template molecules are no longer detectable in the eluent. Then, it is washed three times with 50 ml of deionized water, filtered and dried, and finally vacuum dried at 60 °C for 12 h to obtain an amino acid-based molecularly imprinted polymer / quantum composite material. The material is then ground into particles with an average particle size of 10-30 micrometers.

[0048] The above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material is used to detect amino acids, including the following steps:

[0049] (1) The molecularly imprinted polymer / quantum composite material prepared above was subjected to fluorescence test using a fluorescence spectrophotometer, and its maximum fluorescence emission wavelength was found to be 360 ​​nm.

[0050] (2)

[0051] 1) Take 0.1g of the above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material and add it to a 5mL centrifuge tube. Disperse it in 2mL of distilled water to obtain a composite material dispersion. Take 9 portions of the composite material dispersion and add 5mL of glycine standard solution with concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively to obtain a set of mixed solutions. Shake at 180rpm for 2h and measure the fluorescence value of the set of mixed solutions at a wavelength of 360nm. Plot the obtained fluorescence value on the ordinate and the concentration of glycine standard solution on the abscissa to obtain the working curve of glycine. Take the upper and lower limits of the linear part of the working curve as the working interval for quantitative detection of glycine.

[0052] 2) Take the composite material dispersion described in step 1), add the glycine solution to be tested, and shake under the same conditions as in step 1). Then measure the fluorescence value and calculate the concentration of the glycine molecules to be tested based on the working curve.

[0053] 3) The detection limit of glycine to be tested was determined by using the signal-to-noise ratio method (S / N = 3, where S is the signal intensity and N is the noise intensity), which is the concentration of the analyte when the ratio of the fluorescence emission peak signal to the baseline noise is 3.

[0054] Using the methods described in steps 1)-3) above, the detection limits of each of the other target amino acid molecules (L-alanine, L-valine, L-valine, L-leucine, L-isoleucine, L-leucine) were determined.

[0055] The detection limits and upper and lower limits of concentration for the detection of common isolated amino acids using the composite material of this embodiment are shown in Table 1.

[0056] Table 1. Detection results of amino acids in composite materials

[0057]

[0058] Example 2

[0059] A method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material includes the following steps:

[0060] (1) Weigh 1.1 g of graphene quantum dot material, add it to 15 ml of anhydrous ethanol and ultrasonically disperse for 30-40 minutes to obtain an inorganic quantum dot material dispersion, and store it at 4°C in the dark.

[0061] (2) Take the inorganic quantum dot material dispersion from step (1), add 1.1 g of L-alanine and 1.1 g of L-isoleucine as template molecules, and continue to add 25 g of 3-aminopropyltriethoxysilane, 0.7 g of tetraethyl orthosilicate and 1.7 g of stabilizer 3-mercaptopropionic acid. Then add 22 ml of ammonia water (mass fraction 28%) and 60 ml of deionized water, sonicate for 20-30 min, react at room temperature in the dark for 26 h, and collect the polymerization product by centrifugation.

[0062] (3) The polymerization product from step (2) is loaded into a chromatography column and eluted with 5% ammonia solution until template molecules are no longer detectable in the eluent. Then, it is washed three times with 60 ml of deionized water, filtered and dried, and finally vacuum dried at 60 °C for 12 h to obtain an amino acid-based molecularly imprinted polymer / quantum composite material. The material is then ground into particles with an average particle size of 10-30 micrometers.

[0063] The above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material is used to detect amino acids, including the following steps:

[0064] (1) The molecularly imprinted polymer / quantum composite material prepared above was subjected to fluorescence test using a fluorescence spectrophotometer, and its maximum fluorescence emission wavelength was found to be 530 nm.

[0065] (2)

[0066] 1) Take 0.1g of molecularly imprinted polymer / quantum composite material and add it to a 5mL centrifuge tube. Disperse it in 2mL of distilled water to obtain a composite material dispersion. Take 9 portions of the composite material dispersion and add 5mL of glycine standard solution with concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively to obtain a set of mixed solutions. Shake at 180rpm for 2h and measure the fluorescence value of the set of mixed solutions at a wavelength of 530nm. Plot the obtained fluorescence value on the ordinate and the concentration of glycine standard solution on the abscissa to obtain the working curve of glycine. Take the upper and lower limits of the linear part of the working curve as the working interval for quantitative detection of glycine.

[0067] 2) Take the composite material dispersion described in step 1), add the glycine solution to be tested, and shake under the same conditions as in step 1). Then measure the fluorescence value and calculate the concentration of the glycine molecules to be tested based on the working curve.

[0068] 3) The detection limit of glycine to be tested was determined by using the signal-to-noise ratio method (S / N = 3, where S is the signal intensity and N is the noise intensity), which is the concentration of the analyte when the ratio of the fluorescence emission peak signal to the baseline noise is 3.

[0069] Using the methods described in steps 1)-3) above, the detection limits of each of the other target amino acid molecules (L-alanine, L-valine, L-valine, L-leucine, L-isoleucine, L-leucine) were determined.

[0070] The detection limits and upper and lower limits of concentration for the detection of common isolated amino acids using the composite material of this embodiment are shown in Table 2.

[0071] Table 2. Detection results of amino acids in composite materials

[0072]

[0073]

[0074] Example 3

[0075] A method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material includes the following steps:

[0076] (1) Weigh 1 gram of CdTe quantum dot material, add it to 10 ml of anhydrous ethanol and ultrasonically disperse it for 40 minutes to obtain an inorganic quantum dot material dispersion, and store it at 4°C in the dark.

[0077] (2) Take the inorganic quantum dot material dispersion from step (1), add 1.5 g of L-alanine and 1.5 g of L-isoleucine as template molecules, and continue to add 30 g of 3-aminopropyltriethoxysilane, 0.8 g of tetraethyl orthosilicate and 2 g of stabilizer mercaptoacetic acid. Then add 25 ml of ammonia water (mass fraction 28%) and 70 ml of deionized water, sonicate for 20 min, react at room temperature in the dark for 24 h, and collect the polymerization product by centrifugation.

[0078] (3) The polymerization product from step (2) was loaded into a chromatography column and washed with 5% ammonia solution until no template molecules were detected in the eluent. Then it was washed three times with 50 ml of deionized water, filtered and dried, and finally vacuum dried at 60 °C for 12 h to obtain an amino acid-based molecularly imprinted polymer / quantum composite material. The material was then ground into particles with an average particle size of 10-30 micrometers.

[0079] The above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material is used to detect amino acids, including the following steps:

[0080] (1) The molecularly imprinted polymer / quantum composite material prepared above was subjected to fluorescence test using a fluorescence spectrophotometer, and its maximum fluorescence emission wavelength was found to be 654 nm.

[0081] (2)

[0082] 1) Take 0.1g of molecularly imprinted polymer / quantum composite material and add it to a 5mL centrifuge tube. Disperse it in 2mL of distilled water to obtain a composite material dispersion. Take 9 portions of the composite material dispersion and add 5mL of glycine standard solution with concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively to obtain a set of mixed solutions. Shake at 180rpm for 2h and measure the fluorescence value of the set of mixed solutions at a wavelength of 654nm. Plot the obtained fluorescence value on the ordinate and the concentration of glycine standard solution on the abscissa to obtain the working curve of glycine. Take the upper and lower limits of the linear part of the working curve as the working interval for quantitative detection of glycine.

[0083] 2) Take the composite material dispersion described in step 1), add the glycine solution to be tested, and shake under the same conditions as in step 1). Then measure the fluorescence value and calculate the concentration of the glycine molecules to be tested based on the working curve.

[0084] 3) The detection limit of glycine to be tested was determined by using the signal-to-noise ratio method (S / N = 3, where S is the signal intensity and N is the noise intensity), which is the concentration of the analyte when the ratio of the fluorescence emission peak signal to the baseline noise is 3.

[0085] Using the methods described in steps 1)-3) above, the detection limits of each of the other target amino acid molecules (L-alanine, L-valine, L-valine, L-leucine, L-isoleucine, L-leucine) were determined.

[0086] The detection limits and concentration limits for quantification of common isolated amino acids using the composite material of this embodiment are shown in Table 3.

[0087] Table 3. Detection results of amino acids in composite materials

[0088]

[0089] Example 4

[0090] A method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material includes the following steps:

[0091] (1) Weigh 1 gram of CdS quantum dot material, add it to 10 ml of anhydrous ethanol and ultrasonically disperse it for 30 minutes to obtain an inorganic quantum dot material dispersion, and store it at 4°C in the dark.

[0092] (2) Take the inorganic quantum dot material dispersion from step (1), add 1 g of L-alanine and 1 g of L-isoleucine as template molecules, and continue to add 22 g of 3-aminopropyltriethoxysilane, 1.1 g of tetraethyl orthosilicate and 2.5 g of cysteine ​​as a stabilizer. Then add 20 ml of ammonia (28% by mass) and 60 ml of deionized water, sonicate for 25 min, react at room temperature in the dark for 24 h, and collect the polymerization product by centrifugation.

[0093] (3) The polymerization product from step (2) is loaded into a chromatography column and eluted with 5% ammonia solution until template molecules are no longer detectable in the eluent. Then, it is washed three times with 50 ml of deionized water, filtered and dried, and finally vacuum dried at 60 °C for 12 h to obtain an amino acid-based molecularly imprinted polymer / quantum composite material. The material is then ground into particles with an average particle size of 10-30 micrometers.

[0094] The above-mentioned amino acid-based molecularly imprinted polymer / quantum composite material is used to detect amino acids, including the following steps:

[0095] (1) The molecularly imprinted polymer / quantum composite material prepared above was subjected to fluorescence test using a fluorescence spectrophotometer, and its maximum fluorescence emission wavelength was found to be 550 nm.

[0096] (2)

[0097] 1) Take 0.1g of molecularly imprinted polymer / quantum composite material and add it to a 5mL centrifuge tube. Disperse it in 2mL of distilled water to obtain a composite material dispersion. Take 9 portions of the composite material dispersion and add 5mL of glycine standard solution with concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively to obtain a set of mixed solutions. Shake at 180rpm for 2h and measure the fluorescence value of the set of mixed solutions at a wavelength of 550nm. Plot the obtained fluorescence value on the ordinate and the concentration of glycine standard solution on the abscissa to obtain the working curve of glycine. Take the upper and lower limits of the linear part of the working curve as the working interval for quantitative detection of glycine.

[0098] 2) Take the composite material dispersion described in step 1), add the glycine solution to be tested, and shake under the same conditions as in step 1). Then measure the fluorescence value and calculate the concentration of the glycine molecules to be tested based on the working curve.

[0099] 3) The detection limit of glycine to be tested was determined by using the signal-to-noise ratio method (S / N = 3, where S is the signal intensity and N is the noise intensity), which is the concentration of the analyte when the ratio of the fluorescence emission peak signal to the baseline noise is 3.

[0100] Using the methods described in steps 1)-3) above, the detection limits of each of the other target amino acid molecules (L-alanine, L-valine, L-valine, L-leucine, L-isoleucine, L-leucine) were determined.

[0101] The detection limits and upper and lower limits of concentration for the detection of common isolated amino acids using the composite material of this embodiment are shown in Table 4.

[0102] Table 4. Detection results of amino acids in composite materials

[0103]

[0104] As can be clearly seen from the data listed in the tables of the various embodiments, all molecularly imprinted polymer / quantum composite materials have a wide linear determination range for different aliphatic amino acids, can quantitatively detect target molecules over a wide concentration range, and have detection limits below 3.5 nmol / L.

[0105] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material, characterized in that, The process includes the following steps: (1) Inorganic quantum dot material is uniformly dispersed in anhydrous ethanol to obtain an inorganic quantum dot material dispersion; (2) The inorganic quantum dot material dispersion from step (1) is taken, and two amino acids are added as amino acid template molecules. Then, 3-aminopropyltriethoxysilane, tetraethyl orthosilicate, and a stabilizer are added. Ammonia and deionized water are added and mixed evenly. The mixture is reacted at room temperature in the dark, and the polymerization product is collected by centrifugation; (3) The polymerization product from step (2) is eluted and post-treated to remove the template molecules and obtain the amino acid-based molecularly imprinted polymer / quantum composite material. The inorganic quantum dot material mentioned in step (1) is selected from any one of carbon quantum dots, graphene quantum dots, CdTe quantum dots, or CdS quantum dots, with a particle size of 4. -10nm; the two amino acids mentioned in step (2) are L-alanine and L-isoleucine, with a molar ratio of 1:1; the stabilizer mentioned in step (2) is any one of mercaptoacetic acid, 3-mercaptopropionic acid or cysteine; in steps (1) and (2), the amounts of each component are as follows: 1-2 parts of inorganic quantum dot material; 2-3 parts of amino acid template molecules; 20-30 parts of 3-aminopropyltriethoxysilane; 0.5-1.5 parts of tetraethyl orthosilicate; 1.5-3 parts of stabilizer; the weight-volume ratio of inorganic quantum dot material to anhydrous ethanol is (1-2):(10-20) g / ml; the volume ratio of anhydrous ethanol, ammonia, and deionized water is (10-20):(20-30):(40-80); the mass fraction of ammonia is 28%.

2. The method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material according to claim 1, characterized in that, The uniform dispersion in step (1) is achieved by ultrasonic dispersion for 30-40 minutes.

3. The method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material according to claim 1, characterized in that, The mixing method described in step (2) is ultrasonic dispersion for 20-30 minutes.

4. The method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material according to claim 1, characterized in that, The reaction time described in step (2) is 24-30 hours.

5. The method for preparing an amino acid-based molecularly imprinted polymer / quantum composite material according to claim 1, characterized in that, The elution and post-treatment steps in step (3) are as follows: the polymer product is loaded into a chromatography column, eluted with 5% ammonia solution until template molecules are not detected in the eluent, then washed three times with 100ml to 150ml of deionized water, filtered and dried, and finally vacuum dried at 60℃ for 12h.

6. The amino acid-based molecularly imprinted polymer / quantum composite material prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the amino acid-based molecularly imprinted polymer / quantum composite material as described in claim 6, for the quantitative detection of natural and non-natural aliphatic amino acids, wherein the natural aliphatic amino acids include glycine, L-alanine, L-valine, L-leucine, and L-isoleucine, and the non-natural aliphatic amino acids include L-valine and L-leucine.

8. The application of the amino acid-based molecularly imprinted polymer / quantum composite material according to claim 7, characterized in that, The detection method in the application includes the following steps: (1) performing fluorescence testing on the amino acid-based molecularly imprinted polymer / quantum composite material using a fluorescence spectrophotometer to obtain the maximum fluorescence emission wavelength of the composite material; (2) performing analysis and testing at the maximum fluorescence emission wavelength obtained in step (1): 1) taking 0.1g of the amino acid-based molecularly imprinted polymer / quantum composite material and adding it to a 5mL centrifuge tube, dispersing it in 2mL distilled water to obtain a composite material dispersion; taking 9 portions of the composite material dispersion, and adding a target amino acid at concentrations of 0.05μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1μmol / L, 2μmol / L, 4μmol / L, 8μmol / L, and 16μmol / L respectively. 1) Take 5 ml of each standard solution to obtain a set of mixed solutions. Shake at 180 rpm for 2 h and measure the fluorescence value of each set of mixed solutions. Plot the obtained fluorescence value on the ordinate and the concentration of the standard solution of the target amino acid on the abscissa to obtain the working curve of the target amino acid. Take the upper and lower limits of the linear part of the working curve as the working interval for quantitative detection of the target amino acid molecule; 2) Take the composite material dispersion obtained in step 1) and add the test amino acid solution of the target amino acid. Shake at 180 rpm for 2 h to obtain the test mixed solution. Measure the fluorescence value of the test mixed solution and calculate the concentration of the test amino acid molecule in the test mixed solution according to the working curve; 3) Use the signal-to-noise ratio method, S / N = 3, where S is the signal intensity and N is the noise intensity, to determine the detection limit of the test amino acid molecule.

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