Disposable amperdmetric acetykhoSinesterase biosensor for the detection of organophosphorus pesticides

摘要

An amperometric biosensor based on acetylcholinesterase (AChE) was assembled by simple adsorption of the enzyme on screen-printed electrodes. The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode. The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes. The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity. The lu.1 of enzyme solution containing 1U AChE and 1% BSA were simply dropped on the working electrode surface. The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 M phosphate buffer and 0.1 M KCl. We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 rnin in parathion methyl solution. The lowest detectable amount of parathion methyl was 5xl0~-8M.