有机磷农药残留掌上检测仪的设计

Design of a hand-held organophosphorus pesticide residue detector

设计了一种能够实现现场检测的有机磷农药残留掌上检测仪,其能够快速筛查有机磷农药污染的蔬菜,保障果蔬类农产品市场安全.基于酶抑制率法测量原理,以发光二极管（LED）为光源,设计双光电检测电路,由硅光电二极管进行信号采集,信号经单片机进行数据处理,实现了吸光度值和抑制率数字显示.与传统分光光度计相比,本实验设计的检测仪巧小轻便（127 mm×77 mm×35 mm）、方便携带,可实现现场零距离检测.实验表明,在乐果农药浓度为0.1-1.0μg/mL范围内,抑制率与乐果浓度呈良好线性,相关系数为0.9986,检出限为0.058μg/mL.将其应用于蔬菜中有机磷农药残留的测定,检测结果与国标方法有良好的相关性,能够对蔬菜中有机磷农药残留进行现场快速分析检测,具有实际的应用价值.

In order to sort out vegetables contaminated by organophosphorus pesticide and guarantee the safety of agricultural markets, a hand-held organophosphorus pesticide residue monitor, which can be used in the field test is designed in this paper. The detector is based on the enzyme inhibition method. A light emitting diode light source, a two-photoelectric sensor and silicon photoelectric diode are used for monochromatic source, detection circuit and signal collecting, respectively. The signals are processed by microcontroller to be converted into absorbance values. After digitalization, the absorbance values and inhibition rates are sent by the microcontroller to the liquid crystal display（LCD） module. Compared with traditional spectrophotometer, the detector is small, light and portable（127 mm×77 mm×35 mm） which can be used in the field test. The inhibition rate versus dimethoate concentration is linear over the range of 0.1 to 1.0 μg/mL with the linear correlation coefficient of 0.9986. The detection limitation for organophos- phorus pesticide dimethoate is 0.058 μg/mL. The comparison results for detection of dimethoate residues in the vegetables indicate that there are good relevance between national standard method and the instrument. The designed instrument can be well used for rapid detection of organophosphorus pesticide residues in vegetables.