Design Of Trace Detection System For Food Harmful Additives

Food safety has received more and more attention,and it is the most prominent problem that chemical raw materials were illegally added into food.According to national standards,high-performance liquid chromatography is approved to detect such illegal additives.This technology was a proven method,but it was only used to test in laboratory because of the large equipment,the complicated pre-processing procedures.In response to the needs of different end-users in the field of food safety,a miniaturized device was developed to be suitable for on-site rapid detection of food harmful additives in this paper.On the base of the combination of molecular imprinting technology and sensor technology,a new trace detection system was designed for harmful additives in food.The development of detection sensors and the design of hardware and software of measurement and control systems were studied.Firstly,as a test object,Sudan Red I was developed its magnetic molecularly imprinted polymer(MIP),which was used as a sensitive material of the detection system to specifically detect target substances.Secondly,in view of magnetic molecular imprinting,after the contrastive study of a microelectrode biomimetic sensor and piezoelectric crystal bionic sensor technology,the molecularly imprinted piezoelectric sensor technology was selected as the detection part of the detection system.And the in situ synthesis method was utilized to make the fabrication of the piezoelectric crystal bionic sensor.Thirdly,as the main control chip,MSP430F149 was adopted to control entire system,meanwhile the system hardware circuit is accordingly designed,including the sensor detection circuit,signal processing circuit,channel selection circuit,buttons,and display circuit.Last but not least,the software of the detection system was designed and debugged with hardware.A large number of experiments were carried out on the developed sensor,and its performance was analyzed.The detection limit of the piezoelectric crystal biomimetic sensor reached approximately 5?g/g?7x?/g.Its detection reaction time is 10?20s.The system test results shown that the maximum error(%)about is 0.1359.The detection system designed in the thesis can quickly and accurately detect specific trace harmful additives in foods.Consequently,it can basically meet the design requirements because of its high detection accuracy and the small error.