Pesticide detection method based on HAuCl4-TMB multi-channel colorimetric array and kit

Abstract

The invention discloses a pesticide detection method based on a multichannel colorimetric array of HAuCl4-TMB and a kit, and the kit comprises an acidic buffer solution, a HAuCl4 solution and a 3, 3 ', 5, 5'-tetramethyl benzidine solution. According to the pesticide detection method, six characteristic ultraviolet absorption peaks are formed through a color development reaction system of TMB and HAuCl4, a six-dimensional characteristic vector is formed by utilizing specific changes of the ultraviolet absorption peaks after pesticide is added, and the six-dimensional characteristic vector can be used as a pesticide spectrum fingerprint for principal component analysis or clustering analysis and mode recognition, so that the pesticide spectrum fingerprint detection method is suitable for pesticide spectrum fingerprint detection. And rapid distinguishing of different pesticides can be realized. The method has the characteristics of simple and convenient operation steps, high detection sensitivity and abundant response channels, can finish differentiated detection of various pesticides in a short time, does not need a large instrument in the detection process, and is suitable for field application and popularization.

Description

Technical Field

[0001] This invention belongs to the field of analytical detection technology, specifically relating to a pesticide detection method and kit based on a multi-channel colorimetric array of HAuCl4-TMB. Background Technology

[0002] With the development of modern agriculture, various pesticides are widely used in crop production. However, pesticide residues can harm the environment and human health, making rapid and accurate detection of pesticide residues crucial. Existing pesticide detection methods mainly include high-performance liquid chromatography (HPLC), gas chromatography (GC), and mass spectrometry (MS). These methods are highly sensitive, but suffer from drawbacks such as expensive equipment, complex operation, and long detection cycles, making them unsuitable for rapid on-site detection.

[0003] In recent years, colorimetric sensing methods have attracted attention due to their ease of operation, clear visualization, and low cost. Traditional colorimetric methods are mainly used to analyze single pesticides or a class of pesticides, and their analytical methods are mostly linear, making it difficult to distinguish multiple pesticides simultaneously. Therefore, existing colorimetric detection still has significant limitations in terms of sensitivity, selectivity, and the ability to distinguish multiple pesticides. There is an urgent need for a new multi-channel colorimetric array method that, by acquiring multidimensional color response information and combining it with data analysis methods such as pattern recognition or multidimensional statistical analysis, can achieve rapid, sensitive, and selective detection of multiple pesticides, thereby overcoming the shortcomings of traditional colorimetric methods in distinguishing pesticide types. Summary of the Invention

[0004] Current pesticide colorimetric detection methods are mainly single-channel linear detection methods, which are usually only applicable to specific types of pesticides and difficult to simultaneously distinguish and accurately identify multiple pesticides. In view of this, this invention proposes a pesticide detection method and kit based on a multi-channel colorimetric array of HAuCl4-TMB. Through the colorimetric reaction system of TMB and HAuCl4, six characteristic ultraviolet absorption peaks are formed. Utilizing the specific changes in the ultraviolet absorption peaks after pesticide addition, a six-dimensional feature vector is formed. This six-dimensional feature vector can be used as a pesticide spectral fingerprint, input into principal component analysis or cluster analysis for pattern recognition, enabling rapid differentiation of different pesticides.

[0005] The technical solution of this invention is implemented as follows: In a first aspect, the present invention provides a pesticide detection kit, comprising an acidic buffer solution, a HAuCl4 solution, and a 3,3',5,5'-tetramethylbenzidine solution.

[0006] TMB (3,3',5,5'-tetramethylbenzidine) in aqueous solution is in its reduced form (TMB). Red It is oxidized by HAuCl4 to form TMB. Red and its oxidation state (TMB)Ox ) forms a blue charge-transfer complex (TMB) Red - TMB Ox TMB Red The ultraviolet absorption peaks are located at 210~220nm and 270~280nm, while TMB Red and TMB Ox The ultraviolet absorption peaks are located approximately at 360–380 nm, 640–660 nm, and 860–890 nm. TMB Red -TMB Ox It can be further oxidized to yellow TMB. Ox An absorption peak appears at 440–460 nm. When TMB is oxidized in solution, it does not exist in a single form but in a mixed form; initially, it exists primarily as TMB. Red and TMB Red -TMB Ox The mixture is present, and the solution appears blue overall. As oxidation progresses, the yellow TMB... Ox As the concentration in the solution gradually increases, the yellow and blue colors combine to form a green color. With further oxidation, all TMB in the system is oxidized to TMB. Ox The final solution exhibits a yellow color. This invention controls the degree of TMB oxidation through conditional screening, bringing the solution to a state where it transitions from blue to green. At this point, the UV-Vis absorption spectrum (200-900 nm) of the entire system displays six absorption peaks with appropriate absorbance values. These six UV absorption peaks are also the most numerous absorption peaks that this system can simultaneously exhibit, providing more colorimetric parameters for subsequent pesticide colorimetric analysis.

[0007] TMB Red : (colorless) TMB Red - TMB Ox : (blue) TMB Ox : (yellow) Based on the above technical solutions, the final concentration of the HAuCl4 solution is 1.0~20 μg / mL, and the final concentration of the 3,3',5,5'-tetramethylbenzidine solution is 5.0~50 μg / mL.

[0008] The final concentrations of HAuCl4 solution (1.0–20 μg / mL) and 3,3',5,5'-tetramethylbenzidine (TMB) solution (5.0–50 μg / mL) were determined primarily based on the spectral characteristics of the colorimetric detection system and the linear response range of the instrument. Specifically, when the reagent concentrations are below this range, the colorimetric reaction is insufficient, the obtained UV absorbance approaches the instrument's detection limit, and the signal-to-noise ratio increases significantly, leading to a greater relative error in the measurement and making it difficult to guarantee the accuracy and repeatability of the results. Conversely, when the concentrations are above this range, the absorbance easily exceeds the linear measurement range of a conventional UV spectrophotometer, resulting in insufficient optical path transmittance and absorbance saturation, thus causing systematic deviations in the test data. Based on this, by controlling the final concentrations of HAuCl4 and TMB within the aforementioned defined range, the absorbance of the colorimetric system can be stably placed within the linear response region of the photometer, ensuring the responsiveness and repeatability of the analyte concentration in response to signal changes, thereby significantly improving the sensitivity and measurement reliability of the detection system.

[0009] Furthermore, the final concentrations of HAuCl4 and TMB directly affect the characteristic absorption peaks of the colorimetric system at 210–220 nm, 270–280 nm, 360–380 nm, 440–460 nm, 640–660 nm, and 860–890 nm. The peak shapes of these absorption peaks are mainly regulated by the relative concentrations of the two: when the ratio is appropriate, TMB species in various oxidation states can coexist stably and produce multi-band absorption; if HAuCl4 is in relative excess, the system is pushed towards a single final oxidation state, and the absorption peaks at 270–280 nm and 360–380 nm weaken or disappear accordingly. If HAuCl4 is relatively insufficient, it cannot provide enough oxidative equivalent to drive the effective oxidation of TMB, resulting in insufficient formation of chromogenic products or changes in product distribution. Consequently, the chromogenic reaction system cannot simultaneously produce UV absorption peaks at 210–220 nm, 270–280 nm, 360–380 nm, 440–460 nm, 640–660 nm, and 860–890 nm. The intensity of the absorption peaks depends on the absolute concentrations of both reactants; excessively high concentrations can easily lead to absorbance saturation and peak distortion. Therefore, controlling the concentrations of HAuCl4 and TMB within a defined range maintains an appropriate ratio and reasonable absorbance between the reactants, ensuring the normal appearance and good resolvability of characteristic absorption peaks, thereby guaranteeing the stability and reliability of the detection system.

[0010] Based on the above technical solutions, the acidic buffer solution further includes a BR buffer solution with a pH of 2 to 4.

[0011] Based on the above technical solutions, the final concentration of the HAuCl4 solution is 3.75 μg / mL, and the final concentration of the 3,3',5,5'-tetramethylbenzidine solution is 12.5 μg / mL.

[0012] Based on the above technical solutions, the acidic buffer solution further includes a BR buffer solution with a pH of 3.

[0013] Secondly, the present invention provides a pesticide detection method based on a multichannel colorimetric array of HAuCl4-TMB, using the kit to detect pesticides, comprising the following steps: S1, mixing HAuCl4 solution and 3,3',5,5'-tetramethylbenzidine solution in an acidic buffer solution to obtain a colorimetric reaction system; S2. Mix the pesticide sample to be tested with the colorimetric reaction system to induce a colorimetric reaction and obtain the reaction solution. S3. Measure the difference in ultraviolet absorption peaks of the reaction solution and the colorimetric reaction system at 210~220nm, 270~280nm, 360~380nm, 440~460nm, 640~660nm, and 860~890nm; S4. The difference in ultraviolet absorption peaks is analyzed using data analysis methods to detect pesticides.

[0014] Based on the above technical solutions, the data analysis method further includes multivariate statistical analysis methods, and the variable statistical analysis methods include principal component analysis and hierarchical cluster analysis.

[0015] The ultraviolet absorption peak difference value in step S3 is used as a colorimetric parameter, and multivariate statistical analysis methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) are used to identify and classify the pesticide samples to be tested.

[0016] Pesticide molecules can interact with TMB through their functional groups (such as amino and carbonyl groups). Different interaction mechanisms can cause differences in charge transfer and electron distribution within the system, thus affecting the UV-Vis absorption characteristics. The type of functional group of the analyte has a significant impact on the sensing signal. Pesticides with similar functional group structures exhibit similar spectral responses. For example, Pym, Imi, and Ace molecules all contain a 3-pyridinemethylamine structure, therefore exhibiting similar UV absorption peak signal changes and being grouped into the same subcategory in cluster analysis.

[0017] Based on the above technical solutions, the multi-channel colorimetric array can be further configured with 2 to 6 parallel reaction channels.

[0018] Channel conditions can be adjusted appropriately to obtain color responses with different sensitivities and selectivity.

[0019] Based on the above technical solutions, the final volume of the colorimetric reaction system is further defined as 1-5 mL.

[0020] Based on the above technical solutions, the final volume of the colorimetric reaction system is further 3 mL.

[0021] Based on the above technical solution, the temperature of the colorimetric reaction is further specified as 0~80℃.

[0022] Based on the above technical solutions, the temperature of the colorimetric reaction is further specified as 20~40℃.

[0023] The pesticide sample to be tested is mixed with the colorimetric reaction system, and the ultraviolet absorption spectrum can be recorded on an ultraviolet-visible spectrophotometer.

[0024] Based on the above technical solutions, the dissolved oxygen concentration of the colorimetric reaction system is further specified to be 2-10 mg / L.

[0025] The dissolved oxygen concentration in the colorimetric reaction system was limited to 2–10 mg / L, based on the necessity of dissolved oxygen for the colorimetric process. Experimental results show that the colorimetric reaction cannot occur below approximately 2 mg / L, while a stable and measurable spectral signal can be obtained within this range. Therefore, this range ensures the smooth progress of the colorimetric reaction and guarantees the reliability of the detection.

[0026] Based on the above technical solutions, the dissolved oxygen concentration of the colorimetric reaction system is further improved to 6~8 mg / L.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention acquires multidimensional color response information through a multi-channel colorimetric array, enabling simultaneous differentiation and identification of multiple pesticides. First, HAuCl4 solution and TMB solution are mixed in a preset ratio to construct a multi-channel colorimetric reaction system. Then, the pesticide sample to be tested is introduced into the multi-channel colorimetric reaction system. Through the interaction between the pesticide, HAuCl4, and the substrate, a specific color change pattern is generated. Finally, the color change is recorded and analyzed to obtain the corresponding colorimetric response fingerprint, achieving rapid identification and detection of different pesticides. The detection method provided by this invention features simple operation steps, high detection sensitivity, and rich response channels. It can complete the differentiation and detection of multiple pesticides in a short time. The detection process does not require large instruments and is suitable for on-site application and promotion.

[0028] (2) The colorimetric reaction system provided by the present invention has adjustable conditions, and its sensitivity and selectivity can be optimized.

[0029] (3) The present invention improves the accuracy of analysis through data analysis methods and realizes the ability to distinguish and detect multiple pesticides that are difficult to achieve by traditional colorimetric methods. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a graph showing the absorbance variation at 650 nm of the multi-channel colorimetric array obtained in the anti-interference experiment of Example 1. Figure 2 The fingerprint spectra of 11 different pesticides in Example 2; Figure 3 The PCA score chart for the 11 pesticides in Example 2 is shown below. Figure 4 This is a tree diagram of the HCA of the 11 pesticides in Example 2; Figure 5 The PCA score chart shows the results of five pesticides at three different concentrations in Example 3. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a multi-channel colorimetric array pesticide detection method based on HAuCl4-TMB, the principle of which is as follows: 1. Multi-peak formation system In an acidic buffer solution, TMB and HAuCl4 are mixed in a specific ratio to form a colorimetric reaction system. This system produces six characteristic absorption peaks under UV-Vis spectroscopy (…). ).

[0034] 2. Pesticide-specific disturbances When the pesticide to be tested is added to the colorimetric reaction system, it will produce structure-specific changes in the six absorption peaks, including increased, decreased, or slightly shifted absorbance. Each absorption peak corresponds to a "channel," and the change in peak value is calculated using the system without pesticide as a baseline. This forms a six-dimensional feature vector.

[0035] 3. Data Analysis The six-dimensional feature vector can be used as a spectral fingerprint input for principal component analysis or cluster analysis of pesticides to perform pattern recognition, enabling the differentiation and semi-quantitative analysis of different pesticides. This system is similar to a "fingerprint amplifier," amplifying minute chemical differences into quantifiable spectral features.

[0036] This invention provides a multi-channel colorimetric array pesticide detection method based on HAuCl4-TMB, comprising the following steps: 1. Preparation of mother liquor The concentration of HAuCl4 aqueous solution is 0.1~5 mg / mL; the concentration of TMB ethanol solution is 0.1~5 mg / mL.

[0037] 2. Colorimetric reaction system In an acidic buffer solution (such as BR buffer, pH=3~5), mix TMB and HAuCl4 to a final volume of 1~5 mL to form a stable colorimetric reaction system. The final concentration of HAuCl4 should be 1.0~20 μg / mL, and the final concentration of TMB should be 5.0~50 μg / mL. The preferred conditions are 3.75 μg / mL for HAuCl4 and 12.5 μg / mL for TMB.

[0038] 3. Sample addition and reaction Add the pesticide sample to be tested to the colorimetric reaction system and mix gently; the reaction occurs almost immediately at room temperature.

[0039] 4. Spectroscopic determination The absorption spectrum from 200 to 900 nm was measured using a UV spectrophotometer, and the absorbance of six characteristic peaks was recorded. .

[0040] 5. Data Processing Using the pesticide-free system as a baseline, the six peaks were calculated. A 6-dimensional eigenvector matrix is ​​constructed for PCA or HCA analysis.

[0041] Example 1 This embodiment provides a multi-channel colorimetric array pesticide detection method and kit based on HAuCl4-TMB, including the following steps: First, prepare a 1 mg / mL HAuCl4 aqueous solution and a 1 mg / mL TMB ethanol solution as stock solutions.

[0042] In a BR buffer solution at pH 3, the final concentration of HAuCl4 was 3.75 μg / mL, the final concentration of TMB was 12.5 μg / mL, the total volume was 2.0 mL, and the pH was 3.

[0043] Add CaCl2 solution, NaCl solution, KCl solution, K2SO4 solution, MgSO4 solution and pesticide mancozeb (Man) to HAuCl4 aqueous solution and BR buffer, respectively. Then add TMB ethanol solution, shake well, and the final concentrations are HAuCl4 3.75 μg / mL, TMB 12.5 μg / mL, CaCl2, NaCl, KCl, K2SO4, and MgSO4 100 μg / mL, pesticide Man 6 μg / mL, and total volume 2 mL.

[0044] The colorimetric reaction was performed at room temperature (25°C) with a dissolved oxygen concentration of 6 mg / L.

[0045] The concentrations of CaCl2, NaCl, KCl, K2SO4, and MgSO4 solutions were 10 mg / mL, and the added volume was 20 μL. The concentration of pesticide Man solution was 1 mg / mL, and the added volume was 12 μL.

[0046] The absorbance of each group at 650 nm was measured using a UV-Vis spectrophotometer, and the difference from the baseline was calculated. Each experiment was repeated five times, and the results are as follows: Figure 1 As shown, by Figure 1 It can be seen that the multi-channel colorimetric array of the present invention has good anti-interference effect.

[0047] Example 2 This embodiment provides a multi-channel colorimetric array pesticide detection method and kit based on HAuCl4-TMB, including the following steps: 1. Set up an experimental group and a blank control group: (1) Blank control group: The total volume of the system was 2 mL, with a final concentration of HAuCl4 of 3.75 μg / mL and a final concentration of TMB of 12.5 μg / mL. The colorimetric reaction was carried out at room temperature using a BR buffer solution with a pH of 3, which served as the baseline.

[0048] (2) Experimental group: First, HAuCl4 and BR buffer were premixed with 11 different pesticides (imidacloprid (Imi), glufosinate (Glu), cyfluthrin (Cyf), cyclomethrin (Hex), malathion (Mal), acetamiprid (Ace), pymetrozine (Pym), glyphosate (Gly), Man, cyhalothrin (Cyh), and phoxim (Pho)). The concentration of each pesticide was 1 mg / mL, and the added volume was 12 μL. TMB was then added, resulting in a final concentration of HAuCl4 of 3.75 μg / mL, a final concentration of TMB of 12.5 μg / mL, a final concentration of 6 μg / mL for the 11 pesticides, and a total volume of 2 mL.

[0049] The colorimetric reaction was performed at 40°C with a dissolved oxygen concentration of 8 mg / L.

[0050] After shaking and homogenization, the UV-Vis absorption spectra were recorded on a UV-Vis spectrophotometer, and the absorbance values ​​of the six absorption peaks at 210 nm, 275 nm, 370 nm, 450 nm, 650 nm, and 875 nm were recorded. Each experiment was repeated five times. Finally, PCA and HCA analyses were performed using Origin Lab 2024.

[0051] Example 3 This embodiment provides a multi-channel colorimetric array pesticide detection method and kit based on HAuCl4-TMB, including the following steps: 1. Set up an experimental group and a blank control group: (1) Blank control group: The total volume of the system was 3 mL, with a final concentration of HAuCl4 of 0.1 μg / mL and a final concentration of TMB of 5 μg / mL. The colorimetric reaction was carried out at room temperature using a BR buffer solution with a pH of 2, which served as the baseline.

[0052] (2) Experimental group: First, HAuCl4 and BR buffer were premixed with five different pesticides (Glu, Man, Pho, Ace and Imi) at a concentration of 1 mg / mL, and the added volumes were 4, 12 and 20 μL, respectively. TMB was then added, resulting in a final HAuCl4 concentration of 0.1 μg / mL, a TMB concentration of 5 μg / mL, and final concentrations of five different pesticides (Glu, Man, Pho, Ace, and Imi) of 2 μg / mL, 6 μg / mL, and 10 μg / mL, respectively, for a total volume of 3 mL.

[0053] The colorimetric reaction was performed at 80℃ with a dissolved oxygen concentration of 2 mg / L.

[0054] After shaking and homogenization, the UV-Vis absorption spectra were recorded on a UV-Vis spectrophotometer, and the absorbance values ​​of the six absorption peaks at 210 nm, 275 nm, 370 nm, 450 nm, 650 nm, and 875 nm were recorded. Each experiment was repeated five times. Finally, PCA analysis was performed using Origin Lab 2024.

[0055] Example 4 This embodiment provides a multi-channel colorimetric array pesticide detection method and kit based on HAuCl4-TMB, which differs from Embodiment 1 in that: The final concentration of HAuCl4 was 20 μg / mL, the final concentration of TMB was 50 μg / mL, and the colorimetric reaction was performed at room temperature using a BR buffer solution with a pH of 4, which served as the baseline.

[0056] The colorimetric reaction was performed at 50°C with a dissolved oxygen concentration of 10 mg / L.

[0057] After shaking and homogenization, the UV-Vis absorption spectra were recorded on a UV-Vis spectrophotometer, and the absorbance values ​​of the six absorption peaks at 220 nm, 270 nm, 360 nm, 440 nm, 640 nm, and 860 nm were recorded. Each experiment was repeated five times. Finally, PCA and HCA analyses were performed using Origin Lab 2024.

[0058] Example 5 This embodiment provides a multi-channel colorimetric array pesticide detection method and kit based on HAuCl4-TMB, which differs from Embodiment 1 in that: The total volume of the system was 1 mL, the final concentration of HAuCl4 was 1 μg / mL, the final concentration of TMB was 5 μg / mL, and the colorimetric reaction was carried out at room temperature using BR buffer solution with pH 4 as the baseline.

[0059] After shaking and homogenization, the UV-Vis absorption spectra were recorded on a UV-Vis spectrophotometer, and the absorbance values ​​of the six absorption peaks at 215 nm, 280 nm, 380 nm, 460 nm, 660 nm, and 890 nm were recorded. Each experiment was repeated five times. Finally, PCA and HCA analyses were performed using Origin Lab 2024.

[0060] Comparative Example 1 The difference between this comparative example and Example 2 is that the final concentration of HAuCl4 is 0.5 μg / mL.

[0061] Because the final concentration of HAuCl4 is too low, it cannot provide sufficient oxidative equivalent to drive the effective oxidation of TMB, resulting in insufficient formation of chromogenic products or changes in product distribution. The chromogenic reaction system cannot simultaneously produce ultraviolet absorption peaks at 210~220nm, 270~280nm, 360~380nm, 440~460nm, 640~660nm, and 860~890nm.

[0062] Comparative Example 2 The difference between this comparative example and Example 1 is that the final concentration of HAuCl4 is 50 μg / mL.

[0063] Due to the excessively high final concentration of HAuCl4, the oxidation intensity of the system is significantly increased, causing TMB to be over-oxidized and tend to form a single oxidation state product. This results in the instability of other oxidation intermediates, causing the characteristic absorption peaks in the 270–280 nm and 360–380 nm bands to disappear. Consequently, the colorimetric reaction system cannot simultaneously produce ultraviolet absorption peaks in the 210–220 nm, 270–280 nm, 360–380 nm, 440–460 nm, 640–660 nm, and 860–890 nm bands.

[0064] Performance testing (1) The differences between the six characteristic absorption peaks and the baseline of each group in Example 2 were calculated, and the ΔA values ​​at 210 nm, 275 nm, 370 nm, 450 nm, 650 nm and 875 nm were obtained respectively. In five parallel experiments, we obtained fingerprint spectra for the identification of 11 different pesticides. The results are as follows. Figure 2 As shown. By Figure 2 It is evident that the ΔA value varies depending on the presence of different pesticides.

[0065] (2) The identification results in Example 2 were analyzed using PCA technology, and the results are as follows: Figure 3 The figure shows a PCA score plot that differentiates the ΔA values ​​of colorimetric results for 11 pesticides at a concentration of 6 μg / mL. Each point in the plot corresponds to an independent test. The data points in this PCA score plot show good clustering, each corresponding to one of the 11 pesticides. Pesticides with similar functional group structures (e.g., Pym, Imi, and Ace, all containing a 3-pyridinemethylamine structure) exhibit similar absorption change trends and cluster into the same subcategory in the cluster analysis. This indicates that functional groups in pesticide molecules (such as amino and carbonyl groups) can specifically interact with TMB, thereby affecting the charge distribution and electronic transitions of the system, resulting in distinguishable spectral response characteristics. The ellipse in the figure is a confidence ellipse with a confidence level of 95%. The above experiments demonstrate that this colorimetric system can accurately distinguish different types of pesticides.

[0066] (3) Similarity analysis of 11 pesticides at 6 μg / mL in Example 2 was performed using HCA, and the results are as follows: Figure 4As shown in the HCA tree diagram, the 11 pesticides were correctly classified in multiple tests. The tree diagram reveals that these 11 pesticides can be roughly divided into three clusters. Man, Mal, and Pho exhibit strong attenuation of the absorption peak at 210 nm, moderate attenuation of the absorption peak at 275 nm, and significant enhancement of the absorption peaks at 370 nm, 450 nm, 650 nm, and 875 nm; therefore, they can be grouped into one cluster. Ace, Imi, and Pym pesticides exhibit strong attenuation of the absorption peaks at 210 nm and 275 nm, but have little effect on other absorption peaks; therefore, they can be grouped into another cluster. Gly, Cyh, Hex, Glu, and Cyf have no significant enhancement effect on any peak, and their attenuation effect is also relatively small; therefore, they are grouped into a third cluster. The above results may be related to the chemical structures of these pesticides. Specific functional groups in pesticides interact with the colorimetric system to produce specific absorption peak trends. For example, the three pesticides Pym, Imi, and Ace in the first cluster have similar structures and all contain a 3-pyridinemethylamine structure. The molecular structures of Ace, Man, and Pho in the second cluster all contain sulfur elements, and these similar structural features are also reflected in the HCA analysis results.

[0067] (4) The differences between the six characteristic absorption peaks and the baseline of each group in Example 3 were calculated, and the ΔA values ​​at 210 nm, 275 nm, 370 nm, 450 nm, 650 nm, and 875 nm were obtained. Fingerprint spectra of five pesticides at three concentrations were obtained in five parallel experiments. The identification results were analyzed using PCA technology, such as... Figure 5 Each point in the figure corresponds to an independent experiment, and the confidence level of the confidence ellipse is 95%. The PCA score plots of the five pesticides at three concentrations can be clustered into 15 isolated groups, and the five pesticides can be distinguished at different concentrations. Therefore, it is shown that the HAuCl4-TMB colorimetric sensing system constructed in this invention is suitable for the identification of pesticides at different concentrations.

[0068] In summary, the pesticide detection method and kit based on a HAuCl4-TMB multichannel colorimetric array provided by this invention achieves the differentiation of multiple pesticides and their different concentrations by rationally designing a mixing system of TMB and HAuCl4 to form six characteristic ultraviolet absorption peaks and utilizing the specific changes after pesticide addition to form a six-dimensional spectral fingerprint. This method does not rely on traditional single-peak linear analysis, but combines multichannel ultraviolet absorption data with principal component analysis or cluster analysis to achieve efficient identification of pesticide structural characteristics. The colorimetric system has a rapid response, stable and reliable data, and simple experimental operation, requiring no complex instruments or additional labeling, making it suitable for further applications in agricultural product safety testing and environmental monitoring.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pesticide detection kit, characterized in that, This includes acidic buffer solution, HAuCl4 solution, and 3,3',5,5'-tetramethylbenzidine solution.

2. The pesticide detection kit as described in claim 1, characterized in that, The final concentration of the HAuCl4 solution is 1.0~20 μg / mL, and the final concentration of the 3,3',5,5'-tetramethylbenzidine solution is 5.0~50 μg / mL.

3. The pesticide detection kit as described in claim 1, characterized in that, The acidic buffer solution includes a BR buffer solution with a pH of 2 to 4.

4. The pesticide detection kit as described in claim 2, characterized in that, The final concentration of the HAuCl4 solution is 3.75 μg / mL, and the final concentration of the 3,3',5,5'-tetramethylbenzidine solution is 12.5 μg / mL.

5. The pesticide detection kit as described in claim 3, characterized in that, The acidic buffer solution includes a BR buffer solution with a pH of 3.

6. A pesticide detection method based on a multi-channel colorimetric array of HAuCl4-TMB, characterized in that, The pesticide detection using the kit described in any one of claims 1 to 5 includes the following steps: S1, In an acidic buffer solution, HAuCl4 solution and 3,3',5,5'-tetramethylbenzidine solution are mixed to obtain a colorimetric reaction system; S2. Mix the pesticide sample to be tested with the colorimetric reaction system to induce a colorimetric reaction and obtain the reaction solution. S3. Measure the difference in ultraviolet absorption peaks of the reaction solution and the colorimetric reaction system at 210~220nm, 270~280nm, 360~380nm, 440~460nm, 640~660nm, and 860~890nm; S4. The difference in ultraviolet absorption peaks is analyzed using data analysis methods to detect pesticides.

7. The pesticide detection method as described in claim 6, characterized in that, The temperature for the colorimetric reaction is between 0 and 80°C.

8. The pesticide detection method as described in claim 7, characterized in that, The temperature for the colorimetric reaction is 20~40℃.

9. The pesticide detection method as described in claim 6, characterized in that, The dissolved oxygen concentration in the colorimetric reaction system is 2~10 mg / L.

10. The pesticide detection method as described in claim 9, characterized in that, The dissolved oxygen concentration in the colorimetric reaction system is 6-8 mg / L.

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