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为了快速检测农产品中有机磷农药残留,本文设计了一种基于酶抑制与光谱吸收的农药残留现场检测的光化学传感器。该传感器主要包括光学激发模块、信号处理模块及传感器软件等三部分。此外,传感器还集成了干式恒温系统,控制检测过程中的溶液温度。通过研究了酶促反应的吸光度变化与时间的关系、温度与酶活性的影响,建议选择酶促反应前3mm至5 min内吸光度变化值来计算抑制率,反应选在37℃下进行。传感器对敌敌畏、对硫磷、甲胺磷、乐果的检出限分别为0.015,0.2,0.4,0.5 mg/L,具有较低的检出限。同时,传感器重复性较好,对同一样品的抑制率检测标准偏差仅为0.5293。此外,在实际样品的检测中,传感器检测结果与实验分析方法 -分光光度法与气相色谱法的相关性较好,差异小且无假性结果,进一步证明了传感器检测结果的准确可靠。
In order to quickly detect organophosphorus pesticide residues in agricultural products, a photochemical sensor based on enzyme inhibition and spectral absorption was designed for on-site detection of pesticide residues. The sensor mainly includes three parts: optical excitation module, signal processing module and sensor software. In addition, the sensor integrates a dry thermostat system to control the temperature of the solution during the test. Through the study of the relationship between the change of absorbance and time, temperature and enzyme activity, it is suggested that the inhibition rate should be calculated by the change of absorbance within 3mm to 5min before enzymatic reaction. The reaction was carried out at 37 ℃. The detection limits of dichlorvos, parathion, methamidophos and dimethoate were 0.015, 0.2, 0.4 and 0.5 mg / L, respectively, with lower detection limit. At the same time, the repeatability of the sensor is better, and the standard deviation of the inhibition rate of the same sample is only 0.5293. In addition, in the actual sample testing, the sensor test results and experimental analysis methods - spectrophotometry and gas chromatography correlation is good, the difference is small and no false results, further evidence of the sensor test results are accurate and reliable.