A Weak Current Detection Circuit Design of Organophosphorous Pesticides Rapid Detection Portable Instrument

In this paper, a weak current detection circuit is designed for developing organophosphorous pesticides rapid detection portable instrument. The detection principle is based on the electrochemical characteristic of enzyme catalyzing substrate of acetylcholinesterase biosensor for detecting pesticide residues. Based on the behavior of cyclic voltammograms (CV) of the acetylcholinesterase biosensor, the data acquisition and processing circuit of the weak current signals generated by the biosensor is designed, which including the I/V conversion, differential amplification, low-pass filter, A/D conversion etc. Eventually, the 0 similar to 5V voltage signal are obtained and they are proportional to the weak current from the enzyme biosensor. The designed detection circuit has a good consistence compared with electrochemical analysis instrument, which can establish a good base for developing organophosphorous pesticides rapid detection portable instrument.