Acetylcholinesterase based biosensor for monitoring of Malathion and Acephate in food samples: A voltammetric study

Acetylcholinesterase (AChE) biosensor was developed through silica sol-gel (SiSG) immobilisation of AChE on the carbon paste electrode (CPE) and used as working electrode. AChE catalyses the cleavage of acetylthiocholine chloride (ASChCl or substrate) to thiocholine, which was oxidised to give a disulphide compound by dimerisation at 0.60 V versus saturated calomel electrode. All the experiments were carried out in 0.1 M phosphate buffer solution (PBS) at pH 7.0 and 0.1 M KCl solution at room temperature. The limit of detection and limit of quantification values were found to be 0.058 ppm, 0.044 ppm and 0.194 ppm, 0.147 ppm for Malathion and Acephate, respectively. The response of the biosensor showed a good linearity range with an incubation time of 4 min for Malathion and Acephate, respectively. This biosensor was used for the direct determination of pesticides without any pretreatment and it requires less time for analysis.