Chiang Mai Journal of Science

This research described a sensitive deposable electrochemical biosensor for the detection of organophosphate pesticide based on acetylcholinesterase enzyme (AChE). The pencil graphite electrode was applied as working electrode to modify a disposable biosensor. A 0.5 U mg-1 AChE and 0.25 %wt Chitosan (Chit) were modified as enzyme and conductive polymer to produce PGE/PB/AChE/Chit biosensor by dropping method. Malathion was applied as a pesticide sample in this research. The detection conditions were employed under potential 0.3 V in 0.1 M phosphate buffer solution (pH 7.0) containing 15 mM acetylcholine chloride by chronoamperometry (CA). The PGE/PB/AChE/Chit biosensor exhibited detection limits at 3.0607 ng ml-1. The linear range, sensitivity, response time, reproducibility are 0.5-16.5 ngml-1, 0.8867 mA nM-1, 50 s, 4.43% RSD, respectively. The storage performance at 35 days were 77.97% remained. The proposed biosensor was successfully applied in the determination of malathion pesticide sample.