title: Determination of Parathion and Carbaryl Pesticides in Water and Food Samples Using a Self Assembled Monolayer /Acetylcholinesterase Electrochemical Biosensor.
abstract: An acetylcholinesterase (AchE) based amperometric biosensor was developed by immobilisation of the enzyme onto a self assembled modified gold electrode. Cyclic voltammetric experiments performed with the SAM-AchE biosensor in phosphate buffer solutions (pH = 7.2) containing acetylthiocholine confirmed the formation of thiocholine and its electrochemical oxidation at Ep= 0.28 V vs Ag/AgCl. An indirect methodology involving the inhibition effect of parathion and carbaryl on the enzymatic reaction was developed and employed to measure both pesticides in spiked natural water and food samples without pre-treatment or pre-concentration steps. Values higher than 91-98.0% in recovery experiments indicated the feasibility of the proposed electroanalytical methodology to quantify both pesticides in water or food samples. HPLC measurements were also performed for comparison and confirmed the values measured amperometrically.
authors.affiliation: Instituto de Química, USP, São Paulo, SP, Brazil. valber.pedrosa@gmail.com.
authors.forename: Valber A
authors.initials: VA
authors.lastname: Pedrosa
authors.affiliation: Instituto de Química de São Carlos, USP, São Carlos, SP, Brazil.
authors.forename: Josiane
authors.initials: J
authors.lastname: Caetano
authors.affiliation: Instituto de Química de São Carlos, USP, São Carlos, SP, Brazil.
authors.forename: Sergio A S
authors.initials: SA
authors.lastname: Machado
authors.affiliation: Instituto de Química, USP, São Paulo, SP, Brazil.
authors.forename: Mauro
authors.initials: M
authors.lastname: Bertotti
keywords: Acetylcholinesterase; Biosensor; Creek Water; Food; Pesticides