针对当前农药检测设备所存在的造价高、自动化程度低、试剂耗材量大等问题,提出一种基于纸基微流控芯片的农药光电检测方法.设计一种简单、便携、廉价的纸基微流控芯片.构造桥式复合结构提升微流控酶抑制显色反应的均匀度,设计适用于光吸收反射检测的光路及电路结构,最终创建集化学反应、光吸收反射效应及环境参数控制于一体的便携化农药检测系统试验平台,并对试验平台最佳工艺参数进行测定与优化.试验结果表明:在达到国家检测标准的前提下,所述检测法分辨率可达0.002 mg/L,高于农药速测卡法;在农药检测浓度范围内,所述方法与yps-1 168型便携式农药检测仪检出限相当,但试剂消耗价格降低了94.79％,且检测时间缩短23％.因此设计的纸基微流控芯片农药光电检测系统,为农残检测的便携化研制发展奠定理论基础.%A photoelectric detection method based on paper-based microfluidic chip in pesticide residues is proposed because the existing equipment has the problems of high cost,low degree of automation and large amount of reagent consumables.We design a kind of simple,portable,inexpensive paper-based microfluidic chip,whose bridge composite structure can enhance the uniformity of the color reaction of microfluidic enzyme,and also design the light path and circuit structure suitable for optical absorption reflection detection.The signal amplifying circuit and filter circuit are built to eliminate the interference of clutter and noise in photoelectric detection.Finally,a portable detection system of pesticide residue is established,which is an integrated test platform of the chemical reaction,the reflection effect in light absorption and the control of environment parameters.We observe and optimize the light source,chip placement angle,temperature and other process parameters of test platform in Jiangsu University in 2016.The reflection absorption effect of red LEDs (light-emitting diodes) is tested to be the best among the LEDs with different colors through detecting the paper-based chip color area.The response effect of the system is better when the angle is 10° according to the chip placement angle and reflected voltage data of photoelectric detection during the reaction.It is concluded that light absorption is the most under 35 ℃ and the chemical reaction is the most sufficient via comparing the color effect of the biochemical reaction of enzyme inhibition under different temperatures.We design different concentrations of pesticides,which are used for biochemical reactions of enzyme inhibition in different paper-based microfluidic chips.The resulting product displays blue color region in the paper-based chip,which can be characterized by the color of the different concentrations of pesticides.We use the photoelectric detection device to detect the color zone of the chip;the reflected voltage data can be obtained with this method,which correspond to different concentrations.Based on the experimental data,the model is established by the reflected voltage and the concentration of pesticide.The pesticide residues of test samples can be analyzed quantitatively based on the detection model.It can be concluded from the experimental results that with the method of photoelectric detection,the minimum detection limit of pesticide residues (trichlorfon and parathion) can reach 0.05 mg/L,meeting the national standard,and the resolution can reach 0.002 mg/L,much higher than that with the traditional method.Within the concentration range of pesticide residues,compared with the pesticide residues detector and the rapid detection card,the detection limit for the photoelectric detection is equivalent,but the consumable items are respectively 5.21％ and 41.7％ of the former 2 methods,and the reduction of time is respectively 23％ and 33％.We propose a kind of pesticide residues detection system,which combines the photoelectric detection system and the paper-based microfluidic chip,and possesses the advantages of easy integration and low consumption.The research provides the theoretical basis and realistic foundation for making the pesticide residues detection develop to be portable and universal.
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