Amperometric biosensors based on nafion coated screen-printed electrodes for the determination of cholinesterase inhibitors

Screen-printed electrodes coated with the nafion layer have been investigat ed for cholinesterase biosensor design. The butyrylcholinesterase (ChE) Fro m horse serum was immobilised onto the nafion layer by cross-linking with g lutaraldehyde vapours. The biosensors obtained showed better long-term stab ility and lower wet-king potential in comparison to those obtained with no nafion coating. The sensitivity of a biosensor toward organophosphate pesti cides is not affected by the nafion coating. The detection limits were foun d to be 3.5 x 10(-7) M for trichlorfon and 1.5 x 10(-7) M for coumaphos. (C ) 2000 Elsevier Science B.V. All rights reserved.