Department of Chemistry, Nanchang University, Nanchang 330031, China.
Department of Chemistry, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Modern Analytical Science, Nanchang University, Nanchang 330031, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Mar 5;268:120665. doi: 10.1016/j.saa.2021.120665. Epub 2021 Nov 26.
A colorimetric gold nanoparticles (AuNPs)-based acetylcholinesterase (AChE) assay was designed for the first time to measure the concentration of parathion-methyl (PM) in lake water samples. In this assay, the analyte PM inhibited the hydrolysis of acetylthiocholine (ATCh) by AChE, preventing the formation of thiocholine (TCh) that would otherwise react with the AuNPs catalyst and deactivate the catalyst. Therefore, in the presence of PM, the AuNPs catalyzed the oxidation of the 3,3',5,5'-tetramethylbenzidine (TMB) colorimetric indicator to oxTMB, inducing a visual color change from colorless to blue. However, in the absence of PM, AChE hydrolyzed ATCh to TCh, which then reacted with the AuNPs, preventing the oxidation of TMB to oxTMB and rendering the solution colorless. Therefore, the change in the color of the analyte solution indicated the presence of PM, and the absorbance of the resulting solution was measured by UV-Vis spectroscopy to calculate the concentration of PM after generation of a calibration curve. This method was then employed using the smartphone app Color Picker, which converted the color information from the photos of the solution into digital red (R), green (G), and blue (B) values. The ratio of green (G) to blue (B) (G/B) was then plotted against the corresponding concentration to calculate the standard curve, whose regression equation was expressed by y = -0.012x + 1.02 (ng/mL), and the coefficient of determination (R) was 0.97. In addition, this method was also used to determine the amount of PM in real lake water samples with recovery of 90.2-133.3%.
首次设计了基于比色金纳米粒子（AuNPs）的乙酰胆碱酯酶（AChE）测定法来测量湖水中甲基对硫磷（PM）的浓度。在该测定法中，分析物 PM 抑制 AChE 对乙酰硫代胆碱（ATCh）的水解，从而阻止形成硫代胆碱（TCh），否则 TCh 会与 AuNPs 催化剂反应并使催化剂失活。因此，在 PM 的存在下，AuNPs 催化 3,3',5,5'-四甲基联苯胺（TMB）比色指示剂的氧化，导致从无色到蓝色的视觉颜色变化。但是，在没有 PM 的情况下，AChE 将 ATCh 水解为 TCh，然后 TCh 与 AuNPs 反应，阻止 TMB 氧化为 oxTMB，从而使溶液无色。因此，分析物溶液颜色的变化表明 PM 的存在，并且通过紫外可见光谱法测量所得溶液的吸光度以在生成校准曲线后计算 PM 的浓度。然后，使用智能手机应用程序 Color Picker 采用该方法，该应用程序将溶液的颜色信息转换为数字红（R）、绿（G）和蓝（B）值。然后，将绿色（G）与蓝色（B）的比值（G/B）与相应的浓度作图以计算标准曲线，其回归方程表示为 y = -0.012x + 1.02（ng/mL），决定系数（R）为 0.97。此外，该方法还用于用回收率为 90.2-133.3%的实际湖水样品来测定 PM 的含量。
