A GRAPHENE/ENZYME-BASED ELECTROCHEMICAL SENSOR FOR SENSITIVE DETECTION OF ORGANOPHOSPHORUS PESTICIDES

Abstract

A sensitive and fast sensor for quantitative detection of organophosphorus pesticides (OPs) is obtained using acetylcholinesterase (AChE) biosensor based on graphene oxide (GO)–chitosan (CS) composite film. This new biosensor is prepared via depositing GO–CS composite film on glassy carbon electrode (GCE) and then assembling AChE on the composite film. The GO–CS composite film shows an excellent biocompatibility with AChE and enhances immobilization efficiency of AChE. GO homogeneously disperses in the GO–CS composite films and exhibits excellent electrocatalytic activity to thiocholine oxidation, which is from acetylthiocholine catalyzed by AChE. The results show that the inhibition of carbaryl/trichlorfon on AChE activity is proportional to the concentration of carbaryl/trichlorfon. The detection of linear range for carbaryl is from 10[Formula: see text]nM to 100[Formula: see text]nM and the correlation coefficients of 0.993. The detection limit for carbaryl is calculated to be about 2.5[Formula: see text]nM. In addition, the detection of linear range for trichlorfon is from 10[Formula: see text]nM to 60[Formula: see text]nM and the correlation coefficients of 0.994. The detection limit for trichlorfon is calculated to be about 1.2[Formula: see text]nM. This biosensor provides a new promising tool for trace organophosphorus pesticide detection.