Design Of Pesticide Detection System Based On Colorimetric Sensor Array

Our country is the largest country in the world on using pesticides, the environmental pollution and food safety issues caused by pesticide residues has become increasingly prominent,and this threats the national health seriously. Pesticide residue detection methods can be divided into instrumental analysis method and rapid screening assay. Instrumental analysis method can’t be applied to on-site detection,because it needs large equipment and the detection progress is cumbersome and complex. Rapid screening assay can be used to on-site detection,but its accuracy is not so high. The colorimetric sensor array which emerged in recent years is expected to provide a new method to the detection of pesticide residues.This paper based on preliminary studies which using colorimetric sensor array to detect pesticide residues. The basic principle is the color change when colorimetric sensor array occurs cross response to the tested sample. In this paper,a new type of pesticide detection system based on colorimetric sensor array is designed,and a new experimental methodology based on the system is established. This will help to develop new method to detect pesticide residue based on colorimetric sensor array. The main study work can be expressed as follows:(1) A summary is given on the preliminary studies which using colorimetric sensor array to detect pesticide residues. There are some inadequate in the detect progress of these studies,such as the low degree of automation,rough sampling method,lack of condition monitoring and control,easy to introduce interference patterns. Based on the analysis of the original detection progress,a standardized detection progress is proposed in this paper.(2) Overall structure and function of the system is designed according to the proposed detecting process. The system consists of a host computer and a slave computer:PC is the host computer,it completes sending commands,receiving the information of temperature send from slave computer. What’s more,it completes image acquisition of the colorimetric sensor array. PIC microcontroller is the slave computer,it completes receiving commands from host computer to assist the host computer to control the temperature and the flow of the detection. There are some peripheral modules controlled by the slave computer,they are stepper motor motion control module, temperature monitoring and control module, serial communication module, background light and ultrasonic nebulizer control module. Finally,completes designing and manufacturing of the PCB board.(3) According to the functional requirement of the system,the host computer program and the slave computer program are completed in the environment of VS2008 and MAPLAB. The host computer program mainly to complete image acquisition,serial communication functions and to provide interactive interface. The slave computer program is in accordance with the needs of the detection process,it designed to achieve position control through stepper motor, temperature monitor and control, serial communication and some other functions.(4) Module-level testing and integration testing are conducted to the system,and the system is confirmed to achieve preset function. Finally,the system is used to experimentally detect 3 different pesticides solution,and the experiment results show that the system can correctly distinguish the 3 different pesticides.