Determination of Phoxim Pesticides Using Acetylcholinesterase Biosensor Based on ZnO Nanorods

Using gold-sprayed polycarbonate template as working electrode,ZnO nanorods were prepared by electro-deposition from a solution of ZnCl2 and KCl.The template deposited with ZnO nanorods was adhered and dissolved on surface of polished glassy carbon electrode (GCE).Finally,the acetylcholinesterase (AChE) biosensor was prepared by immobilizing the AchE directly onto the surface of the ZnO nanorods modified GCE.After air-drying,the biosensor,AChE-ZnO/GCE,was ready for use in determination of phoxim pesticides.It was found that in the presence of 0.5 mmol·L-1 hydrosulfoacetylcholine (ATCh),the oxidative peak current was remarkable raised at the AChE-ZnO/GCE in PBS of pH 7.38,but significant lowering of the peak current at the same biosensor,under same condition,was observed when phoxim was added.Linear relationship between the rate of decrease in peak current (I%) and logarithm of concentration of phoxim (a representative object for phoxime pesticides) was found in the range of 9.85×10-6-4.95×10-4mol·L-1.Detection limit (3S/N) of the method found was 5.99×10-6mol·L-1.