Nanoenzyme material and its preparation method and application, Pb 2+ Ion detection method

Abstract

A nanozyme material and a preparation method thereof, relating to the field of ion detection technology, uses Prussian blue to regulate the peroxidase activity of Fe, NA / CDs, and uses Prussian blue as a reducing agent and stabilizer to synthesize gold nanoparticles, which have both peroxidase activity and Raman enhancement effect, and are used for nanozyme-based SERS detection. The present invention also provides a Pb 2+ The rapid detection method of ions utilizes the color change caused by nanozyme oxidation or the additional Raman SERS signal generation. This sensing signal (colorimetric and SERS analysis) comes from the catalytic oxidation reaction of ABTS and TMB, while Pb 2+ The presence of Pb has a specific inhibitory effect on the oxidation process. Based on this, Pb 2+ The rapid detection of colorimetric detection and SERS detection is more complementary and consistent, making the detection more accurate and reliable.

Description

Technical Field

[0001] The present invention relates to the field of ion detection technology, and in particular to nanoenzyme materials and preparation methods and applications thereof, Pb 2+ Ion detection method. Background Art

[0002] Lead ion (Pb 2+ ) is a non-degradable toxic metal ion. It is widely distributed in the environment due to industrial and mining activities, coal combustion and the use of leaded paint / gasoline. The World Health Organization (WHO) recommends that Pb in drinking water 2+ The maximum limit is 10 μg / L, Pb in food 2+ The maximum limit is 0.02~0.5 mg / kg. At the same time, metal preparations containing lead and other substances are pesticides that have serious impacts on agricultural production safety, human and animal health, and environmental safety, and have been listed as one of the banned pesticides in the world and China. Therefore, the determination of Pb 2+ The content of lead is a very important item in food safety testing. At present, the main methods for determining lead include atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), inductively coupled plasma mass spectrometry (ICP-MS), electrochemical method and colorimetric probe method. Among them, the colorimetric probe method has attracted much attention due to its simple and rapid operation and the lack of complex instruments and equipment. In order to achieve Pb 2+ For ultra-sensitive assays, signal amplification is usually required to obtain good sensitivity and low detection limits.

[0003] As a new type of enzyme mimics, nanozymes have many advantages that other traditional enzyme mimics cannot achieve. People can study and utilize the characteristics of nanomaterial enzyme mimics, so that nanozymes have greater application prospects. In recent years, nanozymes, including laccase mimics, have been widely used in food analysis, biosensors, medical diagnosis and industrial production. Surface-enhanced Raman spectroscopy (SERS) greatly enhances the Raman signal of the target substance through precious metal materials such as gold and silver to detect trace substances. In addition to the fingerprint spectrum characteristics, it also has the advantages of simple sample pretreatment, fast detection speed, and less sample required, thus occupying a unique position in the field of food safety detection. Recently, some nanomaterials have been prepared into SERS substrates with satisfactory oxidase-like activity for monitoring the catalytic process of oxidase-like reactions. However, most of these nanomaterials are dispersed into solutions with fewer SERS hotspots during the detection process, resulting in weak SERS enhancement of the adsorbed molecules and difficulty in recovery. Therefore, it is of great significance to develop recyclable dual-functional nanostructures with SERS and enzyme-like activity. Summary of the invention

[0004] The first object of the present invention is to provide a nanoenzyme material and a preparation method thereof, wherein the nanoenzyme material is obtained by assembling iron-doped carbon dots, Prussian blue and gold nanoparticles. The nanoenzyme material has a novel structure, high activity and stability, and can be used in the presence of Pb 2+ It has high application value in ion detection.

[0005] The second object of the present invention is to provide a Pb 2+ The rapid detection method of ions utilizes the above-mentioned nanozyme material to realize two different detection modes: colorimetry / SERS. The results of the two detections are more complementary and consistent, and have higher detection sensitivity and credibility.

[0006] The embodiment of the present invention is achieved as follows:

[0007] A nanozyme material, the nanozyme material is Fe, NA / CDs-PB@AuNPs, the nanozyme material comprises iron-doped norepinephrine carbon dots Fe, NA / CDs, PB loaded on Fe, NA / CDs, and AuNPs distributed on the surface of Fe, NA / CDs.

[0008] A method for preparing the above-mentioned nanozyme material comprises:

[0009] Fe,NA / CDs-PB, H2O2, sodium citrate and HAuCl4 were mixed to form a mixed solution, and the mixed solution was reacted to obtain Fe,NA / CDs-PB@AuNPs.

[0010] A nanozyme material in Pb 2+ Applications in ion detection.

[0011] A Pb 2+ A SERS detection method for ions, comprising:

[0012] The nanozyme material and Pb 2+ The ion solutions are mixed, H2O2 and TMB solutions are added to react, and the reaction solution is detected by Raman spectroscopy.

[0013] A Pb 2+ The method for detecting ions by ultraviolet-visible spectroscopy comprises:

[0014] The nanozyme material and Pb 2+ The ion solutions were mixed, H2O2 and ABTS solutions were added to react, and the reaction solution was detected using UV-visible spectroscopy.

[0015] The beneficial effects of the embodiments of the present invention are:

[0016] The present invention provides a nanozyme material and a preparation method thereof, which uses Prussian blue to regulate the peroxidase activity of Fe, NA / CDs, and synthesizes gold nanoparticles using Prussian blue as a reducing agent and stabilizer, which has both peroxidase activity and Raman enhancement effect, and is used for nanozyme-based SERS detection. The present invention also provides a Pb 2+ The rapid detection method of ions utilizes the color change caused by nanozyme oxidation or the additional Raman SERS signal generation. This sensing signal (colorimetric and SERS analysis) comes from the catalytic oxidation reaction of ABTS and TMB, while Pb 2+ The presence of Pb has a specific inhibitory effect on the oxidation process. Based on this, Pb 2+ The rapid detection of colorimetric detection and SERS detection is more complementary and consistent, making the detection more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 TEM images of Fe,NA / CDs-PB and Fe,NA / CDs-PB@AuNPs provided in Example 1 of the present invention.

[0019] Figure 2 The Pb detected by SERS provided in Example 2 of the present invention 2+ Linear spectrogram and equation;

[0020] Figure 3 The Pb detected by UV-visible spectroscopy provided in Example 3 of the present invention 2+ Linear spectrogram and equation;

[0021] Figure 4 The spectra of TMB oxidation and H2O2 of Fe,NA / CDs, Fe,NA / CDs-PB and Fe,NA / CDs-PB@AuNPs provided in Experimental Example 1 of the present invention;

[0022] Figure 5 The specific experimental detection results under the ultraviolet absorption mode provided in Experimental Example 2 of the present invention;

[0023] Figure 6 This is the specific experimental detection result under the SERS mode provided by Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0025] The following is a detailed description of a nanozyme material, a preparation method and application thereof, and a method for detecting Pb2+ ions in an embodiment of the present invention.

[0026] An embodiment of the present invention provides a nanozyme material, which is Fe, NA / CDs-PB@AuNPs. The nanozyme material includes iron-doped norepinephrine carbon dots Fe, NA / CDs, PB loaded on Fe, NA / CDs, and AuNPs distributed on the surface of Fe, NA / CDs.

[0027] This nanozyme material uses PB (Prussian blue) to regulate the peroxidase activity of Fe,NA / CDs (iron-doped norepinephrine carbon dots), and uses PB as a reductant and stabilizer to synthesize gold nanoparticles. This nanozyme material has both peroxidase activity and Raman enhancement effect, and can be used for nanozyme-based SERS detection.

[0028] The present invention also provides a method for preparing the nanozyme material, which comprises:

[0029] Fe,NA / CDs-PB, H2O2, sodium citrate and HAuCl4 were mixed to form a mixed solution, and the mixed solution was reacted to obtain Fe,NA / CDs-PB@AuNPs.

[0030] The mass ratio of Fe, NA / CDs-PB, H2O2, and sodium citrate is 1:0.02~0.2:1~3; the concentration of HAuCl4 in the mixed solution is 5~20 mg / mL. Within the above ratio range, AuNPs (nano-gold) can be ensured to have a better loading effect.

[0031] Further, Fe, NA / CDs-PB, H2O2, and sodium citrate are mixed in water, and 2-4 liters of water are added per gram of Fe, NA / CDs-PB according to the mass of Fe, NA / CDs-PB. H2O2 preferably uses a solution with a concentration of 30-70 mmol / L. The mixture is stirred at room temperature for 5-10 min to obtain the desired Fe, NA / CDs-PB@AuNPs.

[0032] Optionally, the preparation method of Fe,NA / CDs-PB comprises:

[0033] The hydrochloric acid solution of PB is mixed with Fe, NA / CDs to obtain Fe, NA / CDs-PB; the mass ratio of Fe, NA / CDs to PB is 1: 20 to 60. Within the above ratio range, PB can obtain a better loading effect.

[0034] Furthermore, the concentration of the hydrochloric acid solution is 0.05-0.3 mol / L, and 0.1-0.5 liter of hydrochloric acid solution is added per gram of PB according to the mass of PB to ensure that PB can be dissolved more evenly. The mixture of the hydrochloric acid solution of PB and Fe, NA / CDs is stirred at room temperature for 40-90 min.

[0035] Optionally, the preparation method of Fe,NA / CDs comprises:

[0036] The mixture of norepinephrine bitartrate, ethylenediamine and ferric chloride was reacted at 160-200°C to obtain the carbon dots. The mass ratio of norepinephrine bitartrate, ethylenediamine and ferric chloride was 1:0.2-0.5:0.03-0.15. According to the above ratio, the obtained iron-doped norepinephrine carbon dots were more uniformly doped and had a better reaction effect.

[0037] Norepinephrine bitartrate, ethylenediamine and ferric chloride are mixed in water. According to the mass of norepinephrine bitartrate, 20-40 mL of water is added for each gram of norepinephrine bitartrate. Ultrasound can be used to assist the mixing. The reaction is carried out in a hydrothermal reactor for 8-15 h. After the reaction is completed, it is naturally cooled to room temperature to obtain a brown solution. The brown solution is filtered with a 0.22 μm filter to remove large particles and then centrifuged at high speed (8000-1000 rpm, 10-15 min). The supernatant is vacuum dried to obtain Fe,NA / CDs.

[0038] The present invention also provides a method for preparing the nanoenzyme material in Pb 2+ Applications in ion detection.

[0039] Furthermore, the Pb 2+ The ion detection method includes at least one of the SERS detection method and / or the UV-visible spectrum detection method (i.e., colorimetric detection). Preferably, the SERS detection method and the UV-visible spectrum detection method can be used simultaneously. The results of the UV-visible spectrum detection method and the SERS detection are more complementary and consistent, which can make the detection more accurate and reliable.

[0040] In addition, the embodiment of the present invention also provides a Pb 2+ A SERS detection method for ions, comprising:

[0041] The nanozyme material and Pb 2+The ion solutions are mixed, H2O2 and TMB solutions are added to react, and the reaction solution is detected by Raman spectroscopy.

[0042] TMB (3,3',5,5'-tetramethylbenzidine solution) reacts with H2O2 to oxidize and generate blue oxTMB. By comparing the colors, the Pb 2+ Furthermore, in the SERS spectrum, oxTMB can be observed at 872 cm -1 、1184cm -1 、1330 cm -1 and 1607 cm -1 The SERS characteristic peak at Pb 2+ In the presence of ions, the oxidation reaction will be significantly inhibited, which is reflected in the SERS spectrum, that is, the peak area of ​​the above characteristic peak will be reduced accordingly. -1 The characteristic peak area at the position is relatively large, and the characteristic peak area here is selected to be consistent with the Pb in the standard solution with different concentrations. 2+ The linear regression equation is established by measuring the characteristic peak area of ​​the solution to be tested. 2+ Ion concentration, to achieve Pb 2+ Quantitative detection of ions.

[0043] Optionally, the concentration of the nanozyme material is 0.05~0.2 mg / mL, and the amount added is 50~100 μL. The concentration of the TMB solution is 30~70 mmol / L, and the amount added is 20~50 μL; the concentration of H2O2 is 80~150 mmol / L, and the amount used is 20~50 μL. The SERS detection method is scanned for 10~30 s under the conditions of 785nm excitation light and laser power of 300~1000 mW. Within the above ratio range, for Pb 2+ The detection accuracy and sensitivity of ions are high, and the concentration range can be 0.01~10 mg / L Pb 2+ Detection of ion test solution.

[0044] Furthermore, the embodiment of the present invention also provides a Pb 2+ The method for detecting ions by ultraviolet-visible spectroscopy is characterized by comprising:

[0045] The nanozyme material and Pb 2+ The ion solutions were mixed, H2O2 and ABTS solutions were added to react, and the reaction solution was detected using UV-visible spectroscopy.

[0046] ABTS [2,2'-Azobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] reacts with H2O2 to oxidize and generate blue ox ABTS. By comparing the colors, Pb 2+ ions. Furthermore, oxABTS has a characteristic absorption at 415 nm in the UV absorption spectrum. 2+ In the presence of ions, the oxidation reaction will be significantly inhibited, which is reflected in the UV absorption spectrum, and the corresponding absorbance value will decrease accordingly. The absorbance value at 415 nm is used as the vertical axis, and the Pb content in the standard solution of different concentrations is used as the vertical axis. 2+ The linear regression equation is established with the ion concentration as the horizontal axis. Using this linear regression equation, the Pb in the solution to be tested can be calculated by measuring the absorbance value of the solution to be tested. 2+ Ion concentration, to achieve Pb 2+ Quantitative detection of ions.

[0047] Optionally, the concentration of the nanozyme material is 0.05-0.2 mg / mL, and the amount added is 50-100 μL. The concentration of the ABTS solution is 80-130 mmol / L, and the amount added is 20-50 μL; the concentration of H2O2 is 80-150 mmol / L, and the amount used is 20-50 μL. Within the above ratio range, for Pb 2+ The detection accuracy and sensitivity of ions are high, and the concentration range can be 0.01~10mg / L Pb 2+ Detection of ion test solution.

[0048] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0049] Example 1

[0050] This embodiment provides a nanozyme material, namely Fe,NA / CDs-PB@AuNPs, and the preparation method thereof includes:

[0051] S1. Weigh 1.5 g of norepinephrine bitartrate, 0.5 g of ethylenediamine, and 0.1 g of ferric chloride and dissolve them in 40 mL of ultrapure water. Mix them evenly by ultrasonication. Transfer the solution to a polytetrafluoroethylene-lined hydrothermal reactor and heat it at 180 °C for 10 h. After the reaction is completed, cool it naturally to room temperature to obtain a brown solution. Use a 0.22 μm filter membrane to remove large particles of impurities from the brown solution, then centrifuge it at high speed, and vacuum dry the supernatant to obtain iron-doped norepinephrine carbon dots, namely Fe,NA / CDs.

[0052] S2. 0.04 g of Prussian blue (PB) was uniformly dissolved in 10 mL of 0.1 mol / L hydrochloric acid solution, and then mixed with Fe, NA / CDs in a volume ratio of 1:1 and stirred for 1 h to obtain Fe, NA / CDs-PB, where the concentration of Fe, NA / CDs was 0.1 mg / mL; its scanning electron microscope TEM image is shown in the figure Figure 1 A, from which we can see that the synthesized material is spherical, and it can also be seen that PB self-assembled successfully.

[0053] S3. Dissolve 15mg Fe,NA / CDs-PB, 50mmol / L H2O245μL, and 20mg sodium citrate in 40mL ultrapure water, then add HAuCl4, the concentration of HAuCl4 in the mixture is 10mg / mL, stir for 5min, and Fe,NA / CDs-PB@AuNPs is obtained; its scanning electron microscope TEM image is shown in Figure 1 B, From this, we can see the core-shell morphology of Fe,NA / CDs-PB@AuNPs.

[0054] Example 2

[0055] This embodiment provides a Pb 2+ A SERS detection method for ions, comprising:

[0056] S1. Prepare Pb in different concentration ranges (0.01~1.0 mg / mL) 2+ 200 μL of ion standard solution, 50 μL of 0.1 mg / mL Fe,NA / CDs-PB@AuNPs solution, vortex mixed for 30 s, and reacted for 5 min.

[0057] S2. Add 50 μL of 100 mmol / L H2O2 and 20 μL of 50 mmol / L TMB solution to the above reaction solution, react at room temperature for 10 min, scan for 10 s under the conditions of 785 nm excitation light and 500 mW laser power, and use a portable Raman instrument to perform Raman spectroscopy detection on the mixed solution.

[0058] S3. Based on the SERS spectrum at 1607 cm -1 The peak area of ​​the characteristic peak at is taken as the ordinate, with Pb 2+ The concentration of the ion standard solution is used as the horizontal axis for linear fitting. The test results are as follows: Figure 2 As shown, the linear regression equation is obtained:

[0059] S=-8730.08c+113951.33, R 2 =0.991

[0060] Where S represents 1607 cm -1The peak area of ​​the characteristic peak at, c represents Pb 2+ Concentration of ion standard solution.

[0061] It can be seen that the linear regression equation has a good correlation for Pb concentrations as low as 0.01 mg / L. 2+ Ionic solutions can also respond well and have high sensitivity.

[0062] S4. Measure the solution under test at 1607 cm in the SERS spectrum. -1 The peak area of ​​the characteristic peak at , using the above linear regression equation, calculate the Pb in the solution to be tested 2+ Ion concentration.

[0063] Example 3

[0064] This embodiment provides a Pb 2+ The method for detecting ions by ultraviolet-visible spectroscopy comprises:

[0065] S1. Prepare Pb in different concentration ranges (0.01~1.0 mg / mL) 2+ 200 μL of ion standard solution, 50 μL of 0.1 mg / mL Fe,NA / CDs-PB@AuNPs solution, vortex mixed for 30 s, and reacted for 5 min.

[0066] S2. Add 50 μL of 100 mmol / L H2O2 and 20 μL of 100 mmol / L ABTS solution to the above reaction solution, react at room temperature for 10 min, and measure the UV absorption spectrum using a UV spectrophotometer.

[0067] S3. The absorbance value at 415nm in the UV absorption spectrum is the ordinate, and the Pb 2+ The concentration of the ion standard solution is used as the horizontal axis for linear fitting. The test results are as follows: Figure 3 As shown, the linear regression equation is obtained:

[0068] A=-1.09 c+1.85, R 2 =0.992

[0069] In the formula, A represents the absorbance value at 415nm, c represents Pb 2+ Concentration of ion standard solution.

[0070] It can be seen that the linear regression equation has a good correlation for Pb concentrations as low as 0.01 mg / L. 2+ Ionic solutions can also respond well and have high sensitivity.

[0071] S4. Determine the absorbance value of the test solution at 415nm, and use the above linear regression equation to calculate the Pb content in the test solution. 2+ Ion concentration.

[0072] Test Example 1

[0073] This test example measures the pseudoperoxidase activity of the synthesized material, and the measurement method is as follows:

[0074] S1. Prepare Fe,NA / CDs, Fe,NA / CDs-PB and Fe,NA / CDs-PB@AuNPs into 0.1 mg / mL solutions, take 50 μL of each as test sample, vortex mix for 30 seconds, and react for 5 minutes.

[0075] S2. Add 50 μL of 100 mmol / L H2O2 and 20 μL of 50 mmol / L TMB solution to each of the above test samples, react at room temperature for 10 min, and measure the absorbance at a wavelength of 652 nm to determine the pseudoperoxidase activity of the synthetic material.

[0076] Test results such as Figure 4 As shown by Figure 4 It can be seen that the test sample of Fe,NA / CDs-PB@AuNPs has the maximum absorbance at a wavelength of 652 nm and has the highest pseudoperoxidase activity.

[0077] Test Example 2

[0078] This test example tests the effect of coexisting ions in the solution on Pb 2+ The influence of ion detection, the test method is as follows:

[0079] S1. Prepare Pb with an ion concentration of 1 mg / L 2+ Standard solution, and then prepare 100 times the concentration of K + 、Na + Standard solution, 50 times the concentration of Ni 2+ Mg 2+ 、Zn 2+ , Fe 2+ , Mn 2+ , Cu 2+ Standard solution; 2 times the concentration of Hg 2+ Standard solution and pure water were used as blank control.

[0080] S2. The above standard solutions were tested using the methods of Examples 2 and 3, and the test results were as follows Figure 5 , Figure 6 shown.

[0081] Depend on Figure 5It can be seen that in the UV absorption mode, the ion concentration of each ion standard solution far exceeds that of Pb 2+ In the case of standard solution, its absorbance value is still comparable to that of blank control, both around 1.5 au. 2+ The absorbance of the standard solution dropped significantly to less than 1 au. This indicates that the detection method is effective for Pb 2+ The detection of ions has better specificity.

[0082] Similarly, by Figure 6 It can be seen that in the SERS mode, the ion concentration of each ion standard solution far exceeds that of Pb 2+ In the case of standard solution, the characteristic peak intensity value is basically equivalent to that of blank control, both within 5×10 4 au fluctuates up and down. 2+ The characteristic peak intensity of the standard solution dropped significantly, less than 3×10 4 au. Among them, relatively speaking, Hg 2+ , Fe 2+ Ion Pair Pb 2+ The detection of ions has a weak interference. However, when the SERS mode and UV absorption mode are used together, this interference can be completely avoided. 2+ The detection of ions also has good specificity.

[0083] Test Example 3

[0084] This test example uses the detection methods of Examples 2 and 3 to detect Pb in tobacco leaf samples. 2+ The ion content is determined by the following test method:

[0085] S1. Weigh 0.5000 g of tobacco leaf sample, place it in a 100 mL conical flask, add 10 mL of nitric acid and 0.5 mL of perchloric acid, and heat it on a hot plate to digest. If the digestion solution is brown, add a small amount of nitric acid and digest until white smoke is emitted. The digestion solution is colorless and transparent or slightly yellow. After cooling, transfer the sample solution into a 10 mL volumetric flask with water, dilute to the mark, and mix well for testing. Perform a blank test in the same way.

[0086] S2. The above test solution was tested by the detection methods of Examples 2 and 3, respectively, and the conclusions obtained by the detection were: Pb 2+ The ion concentration was not detected.

[0087] S3. Calculate the recovery and precision as follows:

[0088] Three different concentrations of Pb were added to the tobacco samples. 2+Standard solution (0 mg / kg, 5.0 mg / kg, 10.0 mg / kg). Each concentration was measured three times in parallel, and the spike recovery was calculated, and the relative standard deviation RSD was calculated. The measurement results are shown in Table 1.

[0089] Table 1. Spiked recoveries and RSDs of tobacco leaf samples (n=3)

[0090]

[0091] It can be seen from Table 1 that the measured Pb 2+ The recovery rate of spiked samples was between 95.5% and 103.2%, and the RSD was between 1.3% and 2.5%. The test method provided by the embodiment of the present invention had good accuracy and precision.

[0092] Test Example 4

[0093] This test example adopts the detection method of Examples 2 and 3 to detect Pb in rice samples. 2+ The ion content is determined by the following test method:

[0094] S1. Select rice flour component analysis standard material, GBW(E)100351 as the sample to be tested (Gangyan Nano-Test Technology Co., Ltd.); weigh 0.3000 g of dried rice flour sample, place it in a glass digestion tube, add 5 mL of nitric acid (super pure), tighten the cap, soak overnight, transfer the sample tube to the reaction tank, completely seal the tank, add nitrogen, increase the pressure to 4 000 kPa, set the external chamber temperature to below 40 ℃, and the digestion temperature program is shown in Table 2. After the digestion is completed and the pressure is completely released, take out the sample, transfer it to a 10 mL volumetric flask in turn, mix it evenly, wait for the test, and perform a blank test.

[0095] Table 2 Rice digestion heating program

[0096] step Temperature (℃) Holding time / min Power / W Heating time / min 1 120 10 1600 7 2 150 5 1600 5 3 180 15 1600 10

[0097] S2. The above test solution was tested at 1607cm using the detection method of Example 2. -1 Raman spectroscopy was performed at the site and the Pb content in rice was calculated by substituting it into the linear regression equation. 2+ The concentration is 108.9µg / kg, the standard value is 110 ±10µg / kg, and the measurement result is within the error range.

[0098] The absorbance of the solution to be tested was measured at 415 nm using the detection method of Example 3, and the linear regression equation was substituted to calculate the Pb content in rice. 2+ The concentration is 111.5µg / kg, the standard value is 110 ±10µg / kg, and the measurement result is within the error range.

[0099] Test Example 5

[0100] This test example uses the detection methods of Examples 2 and 3 to detect Pb in vegetable samples. 2+ The ion content is determined by the following test method:

[0101] S1. Select celery standard material GBW10048 as the sample to be tested (Institute of Geophysical and Geochemical Exploration); accurately weigh 1.000 g of vegetable sample, place it in a glass digestion tube, add 5 mL nitric acid (super pure) and 1 mL hydrogen peroxide (super pure) in sequence, cover the lid, transfer the sample tube to the reaction tank, completely seal the tank, add nitrogen, increase the pressure to 4 000 kPa, set the external cavity temperature to below 40 ℃, and the digestion temperature program is shown in Table 3. After the digestion is completed and the pressure is completely released, take out the sample, transfer it to a 25 mL volumetric flask in sequence, mix it evenly, wait for the test, and conduct a blank test.

[0102] Table 3 Vegetable digestion heating program

[0103] step Temperature (℃) Holding time / min Power / W Heating time / min 1 110 15 1500 5 2 150 10 1500 5 3 190 10 1500 5

[0104] S2. The above test solution was tested at 1607cm using the detection method of Example 2. -1 Raman spectroscopy was performed at the site and the Pb content in rice was calculated by substituting it into the linear regression equation. 2+ The concentration is 61.9µg / kg, the standard value is 62.3±1.9µg / kg, and the measurement result is within the error range.

[0105] The absorbance of the solution to be tested was measured at 415 nm using the detection method of Example 3, and the linear regression equation was substituted to calculate the Pb content in rice. 2+ The concentration is 63.2µg / kg, the standard value is 62.3±1.9µg / kg, and the measurement result is within the error range.

[0106] In summary, the present invention provides a nanozyme material and a preparation method thereof, which uses Prussian blue to regulate the peroxidase activity of Fe, NA / CDs, and uses Prussian blue as a reducing agent and stabilizer to synthesize gold nanoparticles, which have both peroxidase activity and Raman enhancement effect, and are used for nanozyme-based SERS detection. The present invention also provides a Pb 2+ The rapid detection method of ions utilizes the color change caused by nanozyme oxidation or the additional Raman SERS signal generation. This sensing signal (colorimetric and SERS analysis) comes from the catalytic oxidation reaction of ABTS and TMB, while Pb 2+ The presence of Pb has a specific inhibitory effect on the oxidation process. Based on this, Pb 2+The rapid detection of colorimetric detection and SERS detection is more complementary and consistent, making the detection more accurate and reliable.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nanozyme material, characterized in that: The nanozyme material is Fe, NA / CDs-PB@AuNPs, and the nanozyme material includes iron-doped norepinephrine carbon dots Fe, NA / CDs, PB loaded on the Fe, NA / CDs, and AuNPs distributed on the surface of the Fe, NA / CDs; wherein PB is Prussian blue.

2. A method for preparing the nanoenzyme material according to claim 1, characterized in that: include: Fe, NA / CDs-PB, H2O2, sodium citrate and HAuCl4 are mixed to form a mixed solution, and the mixed solution is reacted to obtain the Fe, NA / CDs-PB@AuNPs.

3. The preparation method according to claim 2, characterized in that: The mass ratio of the Fe,NA / CDs-PB, the H2O2, and the sodium citrate is 1:0.02~0.2:1~3; in the mixed solution, the concentration of the HAuCl4 is 5~20 mg / mL.

4. The preparation method according to claim 3, characterized in that: The preparation method of the Fe,NA / CDs-PB comprises: The hydrochloric acid solution of the PB is mixed with the Fe, NA / CDs to obtain the Fe, NA / CDs-PB; the mass ratio of the Fe, NA / CDs to the PB is 1:20-60.

5. The preparation method according to claim 4, characterized in that: The preparation method of the Fe,NA / CDs comprises: The method comprises mixing norepinephrine bitartrate, ethylenediamine and ferric chloride, and reacting the mixture at 160-200° C. The mass ratio of the norepinephrine bitartrate, the ethylenediamine and the ferric chloride is 1:0.2-0.5:0.03-0.

15.

6. A nanoenzyme material as claimed in claim 1 in Pb 2+ Applications in ion detection.

7. A Pb 2+ The SERS detection method of ions is characterized by: include: The nanoenzyme material according to claim 1 and Pb 2+ The ion solutions are mixed, H2O2 and TMB solutions are added to react, and the reaction solution is detected by Raman spectroscopy.

8. The SERS detection method according to claim 7, characterized in that: The Raman spectrum of the reaction solution is detected at 1607 cm -1 The characteristic peak at .

9. A Pb 2+ The method for detecting ions by ultraviolet-visible spectroscopy is characterized in that: include: The nanoenzyme material according to claim 1 and Pb 2+ The ion solutions were mixed, H2O2 and ABTS solutions were added to react, and the reaction solution was detected using UV-visible spectroscopy.

10. The UV-visible spectrum detection method according to claim 9, characterized in that: The reaction solution was detected by UV-visible spectroscopy to measure the absorbance at 415 nm.

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