| Ectropis obliqua is a kind of major lepidopterous pest widely distributed in tea garden in the South Yangtze River basin.Meanwhile its larvae very like to eat sprouts of tea plantation and have huge appetites which brings economic loss to tea production,so it is extraordinarily important to find early in the process of prevention and treatment when Ectropis obliqua broke out.sex pheromones released during courtship can be used to monitor the population quantity changes of Ectropis obliqua.but at present those pheromones can only be detected by large laboratory apparatus,and heavy laboratory apparatus are obviously not suitable for monitoring in the field.In view of the above problems,it is extremely necessary to develop a portable Ectropis obliqua sex pheromones detector based on the electrochemical biosensor which has been developed to detect the main components of the pheromones that can be accurate to 10 ppb in the previous study.After studying the mathematical relationship between the concentration of sex pheromones and the number of larvae under laboratory conditions,the hardware circuit and related software for measuring the electrochemical impedance spectrum are designed to measure the population quantity of female larvae in tea garden by combining with impedance detection chips-AD5933.the specific contents of this article are as follows:(1)In order to simulate the actual environment of tea garden,blank experiment,negative control experiment and living experiment of female Ectropis obliqua larvae are designed through cooperative usage of electrochemical biosensor in electrochemical workstation to establish the mathematical relationship between the concentration of sex pheromone and the number of female larvae.(2)After elaborating the electrochemical impedance spectroscopy technology,the working principle and related characteristics of AD5933 are analyzed,and then the system of the AC impedance detection based on the modular mode is designed and built.And those designs include the design of hardware,selection of modules,the design of software and the overall design.Function modules for detection,control,communication and frequency division are involved in the design of hardware and selection of modules.The designs of software functions contain automatic measurement,temperature measurement,frequency division,data transmission,display and so like.the information of impedance is also transmitted to the cloud servers through the SIM900 A GPRS module.a computer software is developed additionally to view the information stored in the database of cloud server.After the system is built,the accuracy and stability of the impedance detection system is verified by testing different values of resistors and capacitors in different ranges of frequency.(3)Sex pheromone detector consists of the impedance detection system constructed above and electrochemical impedance biosensor.to verify the availability of sex pheromone detector,The parallel circuit of the 10 K resistor and the 1 n F capacitor is tested by the electrochemical workstation and the detector respectively.At last,by contrasting the data that electrochemical work station and the detector are used respectively to measure the impedance information of biosensor after fixing the Ectropis obliqua PBP2 on the electrochemical impedance biosensor and adding 10-4 M Z3Z9-67-epoxy-octadecadiene,the feasibility of the detector is verified ultimately. |
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