Determination of Pesticides Based on Their Inhibitory Action on Acetylcholinesterase Using a 2-Phase System

Abstract

A new and simple method has been developed to allow the direct determination of pesticides in samples of vegetable oils via pH transduction. It is based on the inhibitory effect of the pesticides on the enzyme acetylcholinesterase (AChE). The strategy involves the use of a biphasic system composed of an organic phase (the oil) containing the pesticide (carbofuran) and an aqueous phase containing the AChE. The pesticide is extracted from the oil phase at the interface of the two phases which causes the inhibition of AChE and formation of acetic acid that is monitored with a pH meter. The degree of inhibition observed in the Tris-HCl solution is in the same order of magnitude as the one observed in the 2-phase system. This approach is sensitive, accurate, and does not require tedious extraction and sample clean-up. It is, therefore, well suited for rapid screening.

Keywords:

• Acetylcholinesterase
• Carbofuran
• Inhibition
• Oil sample
• 2-phase system

Acknowledgments

This work was financially supported by the research project of bilateral cooperation between Morocco and Tunisia (code 08 TM 29) entitled “Design and Optimization of Biosensors for the Determination of Pollutants.”