Light-addressable Potentiometric Sensor System And Its Applications In Organic Phosphorus Detection

Xu Lei (Physical Electronics) Directed by Pro. Han JinghongThe light-addressable potentiometric sensor (LAPS) is a novel kind of field-effect sensor, which has great ability in light addressing and multi-parameter detection. Because of its many remarkable advantages, LAPS has been a research hotspot, and has been applied in many fields since it was introduced.This paper describes the improvement of the capability of the LAPS control-detection system based on the earlier research of LAPS in our lab. The improved system uses frontside-illumination mode and enhances the response of photocurrent. The system uses a new replaceable chip and has realized the chip separated from the flow injection pool. And according to the new chip, the system is designed to employ a new flow injection pool which has a compact structure. In addition, the new system strengthens the function of the control software and puts automatic data-treating into practice. In this paper many test experiments have been done for the improved system. According to the results of experiments, the stability of detection and the significance of photocurrent normalized are discussed. How the illumination mode, the frequency and the resistance of photocurrent loop affect the response of photocurrent is analyzed in detail. And the pilot study on the real-time detection of LAPS system has been done.For the demand of the technology of multi-parameter detection and environment monitoring, LAPS has been applied in the detection for organophosphorus pesticides in this paper. This paper particularly describes the mechanism of the organophosphorus pesticides detection, investigates the method of the acetylcholinesterase (AchE) immobilized on the LAPS chip, and discusses how the AchE film, the buffer and the acetylcholine substrate influence the performance of the sensor. Finally the way of the preservation of the sensor is given, and the life of the sensor is estimated. The results show that the organophosphorus pesticides detection as a parameter of LAPS has been basically realized.