膜富集结合膜上图像比色法快速检测微量有机磷农药

建立了基于手机图像比色法结合多通道膜富集技术用于微量有机磷农药的快速检测方法. 根据乙酰胆碱酯酶活性受有机磷农药特异性抑制而降低的特点, 以吲哚乙酸酯为底物, 经酶水解生成靛蓝, 利用多通道膜富集装置将有色生成物富集到尼龙微孔滤膜上, 将标准溶液和样品溶液富集在同一张膜的不同位置. 用智能手机拍摄微孔滤膜的数码照片, 利用编制的手机APP软件对照片进行处理, 消除光照、 噪点等的影响, 可实现自动识别标准和未知样品. 通过提取样品颜色信号, 建立了颜色信号与浓度的定量分析模型, 用其检测敌百虫的检出限可达0.030 mg/L. 利用该方法对黄瓜中农药敌百虫的含量进行分析, 加标回收率在95.8%~106.9%之间, 相对标准偏差RSD(n=5)为3.8%~5.4%. 本方法用手机代替光谱仪, 简单实用, 与相关国标方法相比, 灵敏度和准确度均得到显著提高, 具有良好的应用前景.

Rapid Detection of Trace Organophosphorus Pesticides by Membrane Enrichment Combined with Membrane Image Colorimetric†

A new method was developed for the rapid detection of organophosphorus pesticides based on smartphone and multi-channel membrane enrichment. According to the property that the activity of acetylcholinesterase was reduced by the specific inhibition of organophosphorus pesticides, indole acetate was used as a substrate which can be hydrolyzed by enzyme to form indigo. Indigo was enriched on a nylon membrane by the multi-channel membrane enrichment device with which analyte in standard solutions and sample solutions can be enriched on the same membrane at different positions. A mobile APP was developed to detect the membrane. Digital photographs of membrane were collected by the phone. With the APP, the influence of illumination and noise was eliminated and all samples enriched at different positions on the membrane could be identified automatically, the color signal of the samples were extracted, thus a standard curve of the color signal vs. concentration of the pesticide could be regressed. Limit of detection of trichlorfon was estimated being 0.030 mg/L. The content of trichlorfon in cucumber was analyzed with the developed method. The results showed that the recoveries were 95.8%—106.9% with relative standard deviations of 3.8%—5.4%. Using a smartphone but spectrometer, the proposed method is simple and applicable. Comparing with the method of GB/T 5009.100-2003, sensitivity and accuracy are improved significantly. The method showed potential applications in fast detection fields.