Skip to Content
Merck
  • Detection of pesticides using an amperometric biosensor based on ferophthalocyanine chemically modified carbon paste electrode and immobilized bienzymatic system.

Detection of pesticides using an amperometric biosensor based on ferophthalocyanine chemically modified carbon paste electrode and immobilized bienzymatic system.

Biosensors & bioelectronics (2002-12-18)
Anton A Ciucu, Carmela Negulescu, Richard P Baldwin
ABSTRACT

A new highly sensitive amperometric method for the detection of organophosphorus compounds has been developed. The method is based on a ferophthalocyanine chemically modified carbon paste electrode coupled with acetylcholinesterase and choline oxidase co-immobilized onto the surface of a dialysis membrane. The activity of cholinesterase is non-competitively inhibited in the presence of pesticides. The highest sensitivity to inhibitors was found for a membrane containing low enzyme loading and this was subsequently used for the construction of an amperometric biosensor for pesticides. Analyses were done using acetylcholine as substrate; choline produced by hydrolysis in the enzymatic layer was oxidized by choline-oxidase and subsequently H(2)O(2) produced was electrochemically detected at +0.35 V vs. Ag/AgCl. The decrease of substrate steady-state current caused by the addition of pesticide was used for evaluation. With this approach, up to 10(-10) M of paraoxon and carbofuran can be detected.