CN112114016B - Electrochemical method for detecting 3-nitropropionic acid - Google Patents
Electrochemical method for detecting 3-nitropropionic acid Download PDFInfo
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Abstract
The invention discloses an electrochemical method for detecting 3-nitropropionic acid, which comprises the following steps: (1) pretreating an electrode; (2) constructing an acetylcholinesterase biosensor based on a glassy carbon electrode etched by NaOH; (3) preparing a standard solution; (4) drawing a standard curve; the inhibition rate of the acetylcholinesterase activity and the logarithm of the 3-nitropropionic acid concentration are in a good linear relation in a certain range, the linear equation is that y is 20.235x +33.262, in an actual detection sample of the 3-nitropropionic acid, the 3-nitropropionic acid standard solution is replaced by a sample to be detected to inhibit the acetylcholinesterase on a working electrode, the oxidation peak current value of 0.544V is measured in a chlorinated acetylthiocholine solution to calculate the inhibition rate, and the 3-NPA concentration value corresponding to the sample to be detected is calculated through the linear equation, so that the acetylcholinesterase inhibitor is obtained. The method provided by the invention realizes the electrochemical determination of the 3-nitropropionic acid for the first time, and the method is simple to operate, high in sensitivity, good in stability, rapid in detection and low in cost.
Description
Technical Field
The invention belongs to the technical field of electrochemical detection methods, and particularly relates to an electrochemical method for detecting 3-nitropropionic acid in sugarcane by using an acetylcholinesterase biosensor based on a NaOH etched glassy carbon electrode.
Background
3-Nitropropionic acid (3-NPA), a neurotoxin produced by the metabolism of the fungus Citrobacter from moldy sugarcane, is chemically stable and highly toxic, can cause damage to the central nervous system, and severely interferes with the metabolism of intracellular enzymes. When people eat the food by mistake, acute poisoning symptoms such as vomit, dizziness, convulsion and the like are easy to occur, and serious people can die. Therefore, a simple, accurate and sensitive 3-NPA analysis method is established, and the method has important significance for processing, transportation and storage of the sugarcane and treatment of poisoning events.
The method for measuring 3-NPA mainly comprises thin layer chromatography, liquid chromatography, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, ion chromatography and the like. However, these methods all have the disadvantages of complicated sample pretreatment, use of organic reagents with high toxicity, high instrument operation cost, long analysis time and the like. 3-NPA is a substance without electrochemical activity, so that the substance cannot be directly detected by an electrochemical method, and no report about the electrochemical method for detecting the 3-NPA is found at present.
The method for etching the glassy carbon electrode by NaOH is characterized in that the electrode is activated in an alkaline solution, so that a functional group layer such as carboxyl, quinoid molecules, carbonyl and the like is formed on the surface of the glassy carbon electrode. Meanwhile, after the glassy carbon electrode is etched by NaOH, a plurality of irregular microspherical substances are formed on the surface of the electrode, the roughness of the surface is changed, the effective surface area of the electrode is increased, the transfer performance of electrons is improved, and more binding sites are provided for the assembly of the sensor.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.
Disclosure of Invention
Aiming at the technical problems, the invention provides an electrochemical method for detecting 3-NPA in sugarcane by using an acetylcholinesterase biosensor based on a NaOH etched glassy carbon electrode.
The invention provides an electrochemical method for detecting 3-NPA in sugarcane by using an acetylcholinesterase biosensor etched by NaOH as a substrate, wherein the acetylcholinesterase biosensor etched by NaOH is constructed by using a glassy carbon electrode etched by NaOH as a substrate and providing a good bonding interface for acetylcholinesterase by using the characteristics of large surface area, many active sites, excellent conductivity and the like of the electrode. In electrochemical assays, acetylcholinesterase (AChE) can catalyze the hydrolysis of acetylthiocholine chloride (ATCl) to generate electroactive thiocholine, which generates an electrochemical signal. And then the inhibition effect of 3-NPA on acetylcholinesterase is utilized, so that the yield of thiocholine is reduced, the oxidation current is correspondingly reduced, and further, the quantitative relation between the inhibition rate of enzyme activity and the logarithm of 3-NPA concentration is established through the change of current, and the 3-NPA is rapidly and sensitively detected.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
an electrochemical method for detecting 3-nitropropionic acid, comprising the following operating steps:
(1) electrode pretreatment: polishing a Glassy Carbon Electrode (GCE) with a diameter of 3mm to a mirror surface with alumina, and sequentially polishing with HNO 3 Ultrasonically cleaning the mixture with ethanol and ultrapure water, and naturally drying the mixture in the air for later use;
(2) the construction of the acetylcholinesterase biosensor based on the NaOH etching glassy carbon electrode comprises the following steps: placing the electrode pretreated in the step (1) in NaOH solution, scanning multiple sections of cyclic voltammetry at a sweep rate of 50mV/s within the range of 0-2.0V, washing the electrode with ultrapure water after current is stable, naturally drying in the air to obtain a NaOH/GCE modified electrode, then mixing acetylcholinesterase (AChE) and Chitosan (CS), dropping 6 mu L of mixed solution (AChE-CS) on the surface of the NaOH/GCE modified electrode obtained after drying, and drying overnight at the environment of 4 ℃ to obtain AChE-CS/NaOH/GCE;
(3) preparation of a standard solution: accurately weighing a 3-nitropropionic acid (3-NPA) standard substance, dissolving the standard substance by using 0.1mol/L phosphate buffer solution, diluting the solution, and fixing the volume to prepare a 3-nitropropionic acid mother solution with the concentration of 1.0 mg/mL; respectively measuring 3-nitropropionic acid mother liquor with different volumes, adding 0.1mol/L phosphoric acid buffer solution (PSB), and obtaining a series of standard solutions to be measured with different concentrations after constant volume;
(4) drawing a standard curve: taking the AChE-CS/NaOH/GCE prepared in the step (2) as a working electrode, taking a saturated calomel electrode as a reference electrode, taking a platinum wire electrode as a counter electrode, respectively immersing the AChE-CS/NaOH/GCE electrode prepared in the step (2) into the 3-nitropropionic acid standard solutions prepared in the step (3) for inhibition, then inserting a three-electrode system into an acetylthiocholine chloride solution (ATCl), carrying out differential pulse voltammetry scanning within the range of 0.2-0.80V, recording the oxidation peak current value at 0.544V, calculating the inhibition rate through a DPV curve, determining the optimal linear range and detection limit of the 3-nitropropionic acid, and expressing the inhibition rate of the 3-nitropropionic acid on acetylcholinesterase by a formula (1):
inhibition ratio [ (I) 0 –I 1 )/I 0 ]×100％ (1)
Wherein, I 0 The peak current, I, measured in a thiocholine chloride solution before the inhibition of the AChE-CS/NaOH/GCE in a standard solution of 3-nitropropionic acid 1 The peak current is measured in an acetylthiocholine chloride solution with the same concentration after the inhibition of 3-nitropropionic acid standard solutions with different concentrations;
the inhibition rate of the acetylcholinesterase activity and the logarithm of the 3-nitropropionic acid concentration are in good linear relation in the range of 0.1-30 mu g/L, and the linear equation is as follows: y is 20.235x +33.262, and the correlation coefficient R is 0.997; wherein y is the inhibition rate (%), and x is the logarithm of the concentration of 3-nitropropionic acid (μ g/L); the detection limit of the method is as follows: 0.05 mu g/L;
in the actual detection of a sample 3-nitropropionic acid, replacing the 3-nitropropionic acid standard solution with a sample to be detected to inhibit acetylcholinesterase on a working electrode, calculating the inhibition rate according to the oxidation peak current value of 0.544V measured in an acetylcholine chloride solution (ATCl), and calculating the 3-NPA concentration value corresponding to the sample to be detected through the linear equation.
Preferably, the electrochemical workstation used in the electrochemical method for detecting 3-nitropropionic acid is model CHI660E, and the parameters of the differential pulse voltammetry are set as follows: the potential amplification was 4mV, the amplitude was 50mV, and the pulse width was 0.2 s.
Preferably, the glassy carbon electrode in the step (1) is polished into a mirror surface by using 0.3 μm and 0.05 μm aluminum oxide respectively; the HNO 3 Is 1:1HNO 3 The ethanol is absolute ethanol.
Preferably, in the electrochemical method for detecting 3-nitropropionic acid, the detection object is 3-nitropropionic acid in sugarcane.
Preferably, in the step (2), the concentration of the acetylcholinesterase is 0.08U/. mu.L, the mass fraction of the chitosan is 0.16%, and the volume ratio of the mixture of the acetylcholinesterase and the chitosan is 1: 4.
Preferably, the concentration of NaOH in the step (2) is 0.1mol/L, and the number of cyclic voltammetry scan stages is 50.
Preferably, the phosphate buffer solution used in step (3) has a pH of 7.5.
Preferably, the inhibition time in step (4) is 12 min.
Preferably, the preparation method of the acetylthiocholine chloride (ATCl) solution in the step (4) comprises the following steps: 0.0108g of a solid acetylthiocholine chloride was weighed out accurately, dissolved in 0.1mol/L, pH Phosphate Buffer Solution (PBS) of 7.5, and taken up in a 10mL volumetric flask to obtain a 5.5mmol/L acetylthiocholine chloride (ATCl) solution.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method applies the glassy carbon electrode etched by NaOH to the preparation of the acetylcholinesterase electrochemical biosensor for the first time, obviously improves the intensity and stability of current signals, and improves the detection sensitivity of the electrochemical sensor;
(2) the inhibition rate of the activity of the acetylcholinesterase and the logarithm of the concentration of the 3-nitropropionic acid have good linear relation in the range of 0.1-30 mu g/L;
(3) the method disclosed by the invention realizes the electrochemical determination of the 3-nitropropionic acid for the first time based on the inhibition effect of the 3-nitropropionic acid on acetylcholinesterase, and has the advantages of simplicity in operation, high sensitivity, good stability, rapidness in detection and low cost.
Drawings
FIG. 1 is a graph of DPV curves of AChE-CS/GCE (curve a) constructed based on bare glassy carbon electrodes and AChE-CS/NaOH/GCE (curve b) constructed based on NaOH-etched glassy carbon electrodes according to the present invention in a 5.5mmol/L ATCl solution.
FIG. 2 is a DPV curve diagram of the AChE-CS/NaOH/GCE electrode constructed by the present invention before inhibition (curve a) and after inhibition (curve b) by 1 μ g/L3-nitropropionic acid standard solution.
FIG. 3 is a DPV response graph of an AChE-CS/NaOH/GCE electrode constructed according to the present invention after 12-minute inhibition in standard solutions containing 5.5mmol/L ATCl to record 3-nitropropionic acid at different concentrations; wherein, the a-i curves respectively show DPV curves of the electrode after 12 minutes of inhibition in 3-nitropropionic acid standard solutions with the concentrations of 0,0.1,0.3,1.0,3.0,5.0,7.0,10.0 and 30.0 mu g/L.
FIG. 4 is a graph of the log of the concentration of a standard solution of 3-nitropropionic acid calibrated to the inhibition of acetylcholinesterase.
Detailed Description
The following detailed description is to be read in connection with the accompanying drawings, but it is to be understood that the scope of the invention is not limited to the specific embodiments. The raw materials used in the examples were all commercially available unless otherwise specified. The electrochemical workstation used in the following examples was of type CHI660E, and the differential pulse voltammetry parameters were set as follows: the potential amplification was 4mV, the amplitude was 50mV, and the pulse width was 0.2 s.
Example 1
An electrochemical method for detecting 3-nitropropionic acid comprises the following operation steps:
(1) electrode pretreatment: polishing Glassy Carbon Electrode (GCE) with diameter of 3mm with 0.3 μm and 0.05 μm aluminum oxide respectively to obtain mirror surface, sequentially polishing with 1:1HNO 3 Ultrasonically cleaning the mixture by absolute ethyl alcohol and ultrapure water, and naturally drying the mixture in the air for later use;
(2) the method comprises the following steps of (1) constructing an acetylcholinesterase biosensor based on a glassy carbon electrode etched by NaOH: placing the electrode pretreated in the step (1) in 0.1mol/L NaOH solution, scanning 50 sections under cyclic voltammetry at a sweep rate of 50mV/s in the range of 0-2.0V, after the current is stabilized, washing the electrode with ultrapure water, naturally drying in the air to obtain a NaOH/GCE modified electrode, then mixing acetylcholinesterase (AChE, 0.08U/muL) and chitosan (CS, wt ═ 0.16%) according to a volume ratio of 1:4, dripping 6 muL of mixed solution (AChE-CS) on the surface of the dried NaOH/GCE modified electrode, drying overnight at the environment of 4 ℃, and obtaining AChE-CS/NaOH/GCE, namely the acetylcholinesterase biosensor based on the NaOH etching glassy carbon electrode;
meanwhile, an acetylcholinesterase biosensor (AChE-CS/GCE) constructed by a bare glassy carbon electrode was prepared under the same conditions as a control of an AChE-CS/NaOH/GCE modified electrode, as shown in fig. 1;
(3) preparation of a standard solution: accurately weighing a 3-NPA standard substance, dissolving the 3-NPA standard substance by using a phosphoric acid buffer solution with the value of 0.1mol/L, pH of 7.5, diluting and fixing the volume to prepare a 3-nitropropionic acid mother solution with the concentration of 1.0 mg/mL; respectively measuring 3-NPA mother liquor with different volumes, adding phosphoric acid buffer solution with the value of 7.5 of 0.1mol/L, pH, and obtaining a series of standard solutions to be measured with different concentrations after constant volume;
(4) drawing a standard curve: preparation of acetylthiocholine chloride (ATCl) solution: accurately weighing 0.0108g of solid acetylthiocholine chloride, dissolving the solid acetylthiocholine chloride with 0.1mol/L, pH value of 7.5 phosphate buffer solution, and placing the dissolved acetylthiocholine chloride in a 10mL volumetric flask to obtain 5.5mmol/L of acetylthiocholine chloride (ATCl) solution for later use; taking the AChE-CS/NaOH/GCE prepared in the step (2) as a working electrode, taking a saturated calomel electrode as a reference electrode, taking a platinum wire electrode as a counter electrode, respectively immersing the AChE-CS/NaOH/GCE electrode prepared in the step (2) into the 3-NPA standard solutions with different concentrations prepared in the step (3) for inhibition for 12min, then inserting a three-electrode system into the spare ATCl solution with 5.5mmol/L, performing differential pulse voltammetry scanning (DPV) within the range of 0.2-0.8V, recording the oxidation peak current value about 0.544V, calculating the inhibition rate through a DPV curve, establishing a standard curve, and expressing the inhibition rate of the 3-NPA on acetylcholinesterase by a formula (1):
inhibition rate [ [ (I) 0 –I 1 )/I 0 ]×100％ (1)
Wherein, I 0 The peak current, I, measured in a thiocholine chloride solution before the inhibition of the AChE-CS/NaOH/GCE in a standard solution of 3-nitropropionic acid 1 Peak currents measured in the same concentration of thiocholine chloride solution after 12min inhibition in different concentrations of 3-nitropropionic acid standard solution, as shown in FIGS. 2-3;
the inhibition rate of acetylcholinesterase activity was well linear with the logarithm of 3-NPA concentration in the range of 0.1-30. mu.g/L, as shown in FIG. 4, and the linear equation is: y is 20.235x +33.262, and the correlation coefficient R is 0.997; wherein y is an inhibition rate (%), and x is a logarithm of the concentration of 3-NPA (. mu.g/L); the detection limit of the method is as follows: 0.05 mu g/L;
and (3) determination of a sample to be tested: peeling sugarcane, cutting into small pieces, grinding and crushing in a grinder, putting 5.0000g of sample powder into a 50mL centrifuge tube, adding 40mL of PBS (phosphate buffer solution) with the concentration of 0.1mol/L, pH being 7.5, performing ultrasonic extraction for 60min, centrifuging at 6000rpm for 6min, and taking 10mL of supernatant to be tested; and (4) performing electrochemical test according to the method and the steps of drawing the standard curve, calculating the inhibition rate according to the measured current value, and calculating the 3-NPA concentration value corresponding to the sample to be tested by the linear equation.
Respectively adding a certain amount of 3-NPA into the sample to be detected, so that the concentrations of the added 3-NPA in the sample are respectively as follows: the recovery of the spiked samples was calculated under the same conditions as 0.5. mu.g/L, 3.0. mu.g/L, and 10.0. mu.g/L, and the results of the measurement of the sample and spiked recovery are shown in Table 1:
TABLE 1 Standard addition recovery determination results of 3-NPA in sugarcane samples
| Numbering | Sample content (μ g/L) | Scalar quantity (mu g/L) | Measured value (μ g/L) | Recovery (%) |
| 1 | 0.1229 | 0.5000 | 0.6059 | 96.6 |
| 2 | 0.1229 | 3.0000 | 3.3059 | 106.1 |
| 3 | 0.1229 | 10.0000 | 9.6929 | 95.7 |
As can be seen from Table 1, the standard recovery rates of the method are respectively 96.6%, 106.1% and 95.7%, and are all more than 95%.
As can be seen from FIG. 1, the response current of AChE-CS/NaOH/GCE in 5.5mmol/L ATCl solution is significantly greater than that of AChE-CS/GCE, which shows that the AChE-CS/NaOH/GCE of the invention significantly improves the intensity and stability of catalytic current signals, and improves the sensitivity and stability of the analysis method.
As can be seen from FIG. 2, after 3-NPA inhibition, the response current (curve b) of AChE-CS/NaOH/GCE in 5.5mmol/L ATCl solution is obviously smaller than that before inhibition (curve a), which indicates that 3-NPA has significant inhibition effect on acetylcholinesterase (AChE), and provides quantitative detection basis for detecting 3-NPA by enzyme inhibition method.
As can be seen from FIG. 3, the response current of AChE-CS/NaOH/GCE in 5.5mmol/L ATCl solution decreases with the increase of 3-NPA concentration, which provides the basis for the calibration curve of FIG. 4.
As can be seen from FIG. 4, the logarithm of the 3-NPA concentration has a better linear relationship with the inhibition rate of acetylcholinesterase, and the content information of 3-NPA can be obtained through the calibration curve.
The invention establishes the electrochemical detection of 3-NPA by using an enzyme inhibition method for the first time, and the detection mechanism of the 3-NPA is that the acetylcholinesterase (AChE) can catalyze the hydrolysis of chloroacetylthiocholine (ATCl) to generate the thiocholine with electrochemical activity and generate an electrochemical signal. When the activity of acetylcholinesterase (AChE) is inhibited by 3-NPA, the yield of thiocholine is reduced, the oxidation current is correspondingly reduced, and then the quantitative relation between the inhibition rate of the enzyme activity and the logarithm of the 3-NPA concentration is established through the change of the current, so that the detection of the 3-NPA can be realized.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (8)
1. An electrochemical method for detecting 3-nitropropionic acid, comprising the following steps:
(1) electrode pretreatment: polishing glassy carbon electrode with alumina to obtain mirror surface, and sequentially polishing with HNO 3 Ultrasonically cleaning ethanol and ultrapure water, and naturally drying for later use;
(2) the method comprises the following steps of (1) constructing an acetylcholinesterase biosensor based on a glassy carbon electrode etched by NaOH: placing the electrode pretreated in the step (1) in NaOH solution, scanning multiple sections of cyclic voltammetry at a sweep rate of 50mV/s within the range of 0-2.0V, washing the electrode with ultrapure water after current is stabilized, naturally drying to obtain a NaOH/GCE modified electrode, mixing acetylcholinesterase and chitosan, dripping 6 mu L of mixed liquid on the surface of the dried NaOH/GCE modified electrode, drying overnight to obtain AChE-CS/NaOH/GCE, namely the acetylcholinesterase biosensor based on the NaOH etched glassy carbon electrode;
(3) preparation of a standard solution: accurately weighing a 3-nitropropionic acid standard substance, dissolving the 3-nitropropionic acid standard substance by using 0.1mol/L phosphate buffer solution, diluting, fixing the volume, and preparing a 3-nitropropionic acid mother solution with the concentration of 1.0 mg/mL; respectively measuring 3-nitropropionic acid mother liquor with different volumes, adding 0.1mol/L phosphoric acid buffer solution (PBS), and performing constant volume to obtain a series of standard solutions to be measured with different concentrations;
(4) drawing a standard curve: taking the AChE-CS/NaOH/GCE prepared in the step (2) as a working electrode, taking a saturated calomel electrode as a reference electrode, taking a platinum wire electrode as a counter electrode, respectively immersing the AChE-CS/NaOH/GCE electrode prepared in the step (2) into the 3-nitropropionic acid standard solutions prepared in the step (3) to inhibit, then inserting a three-electrode system into an acetylthiocholine chloride solution, carrying out differential pulse voltammetry scanning within the range of 0.2-0.80V, recording the oxidation peak current value at 0.544V, calculating the inhibition rate through a DPV curve, and determining the optimal linear range and detection limit of the 3-nitropropionic acid, wherein the inhibition rate of the 3-nitropropionic acid on acetylcholinesterase can be expressed by the formula (1):
inhibition ratio [ (I) 0 –I 1 )/I 0 ]×100％ (1)
Wherein, I 0 The peak current, I, measured in a thiocholine chloride solution before the inhibition of AChE-CS/NaOH/GCE in a 3-nitropropionic acid standard solution was measured 1 The peak current is measured in an acetylthiocholine chloride solution with the same concentration after the inhibition of 3-nitropropionic acid standard solutions with different concentrations;
the inhibition rate of the acetylcholinesterase activity and the logarithm of the 3-nitropropionic acid concentration are in a good linear relation within the range of 0.1-30 mu g/L, and the linear equation is as follows: y is 20.235x +33.262, and the correlation coefficient R is 0.997; wherein y is the inhibition rate, and x is the logarithm of the concentration of the 3-nitropropionic acid; the detection limit of the method is as follows: 0.05 mu g/L;
in the actual detection of the sample 3-nitropropionic acid, replacing the 3-nitropropionic acid standard solution with a sample to be detected to inhibit acetylcholinesterase on the working electrode, calculating the inhibition rate according to the oxidation peak current value of 0.544V measured in the chlorinated acetylthiocholine solution, and calculating the 3-NPA concentration value corresponding to the sample to be detected through the linear equation to obtain the target product.
2. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: polishing glassy carbon electrodes in the step (1) into mirror surfaces by using 0.3 mu m and 0.05 mu m of aluminum oxide respectively; the HNO 3 Is 1:1HNO 3 The ethanol is absolute ethanol.
3. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: in the electrochemical method for detecting the 3-nitropropionic acid, a detection object is the 3-nitropropionic acid in the sugarcane.
4. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: in the step (2), the concentration of the acetylcholinesterase is 0.08U/mu L, the mass fraction of the chitosan is 0.16%, and the volume ratio of the mixture of the acetylcholinesterase and the chitosan is 1: 4.
5. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: in the step (2), the concentration of NaOH is 0.1mol/L, and the number of cyclic voltammetry scanning sections is 50 sections.
6. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: the pH of the phosphoric acid buffer solution used in step (3) was 7.5.
7. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein: the inhibition time in step (4) was 12 min.
8. The electrochemical method for detecting 3-nitropropionic acid of claim 1, wherein the acetylthiocholine chloride (ATCl) solution preparation method in step (4) is: 0.0108g of solid acetylthiocholine chloride is weighed out accurately, dissolved in 0.1mol/L, pH phosphoric acid buffer solution with a value of 7.5, and taken up in a 10mL volumetric flask to obtain a 5.5mmol/L acetylthiocholine chloride solution.
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Application publication date: 20201222 Assignee: Gaoshi Ruilian (Tianjin) Photoelectric Technology Co.,Ltd. Assignor: GUANGXI ACADEMY OF AGRICULTURAL SCIENCES Contract record no.: X2023980046284 Denomination of invention: An Electrochemical Method for Detecting 3-Nitropropionic Acid Granted publication date: 20220923 License type: Common License Record date: 20231108 |