Patulin Determination at Screen Printed Electrodes by Square Wave Voltammetry

Introduction: Patulin is a mycotoxin commonly encountered in juices and is not readily degraded by thermal processing. Given the stability of the toxin the main means of control is through screening raw juice or concentrate using laboratory based techniques such as HPLC. In this respect there is a demand for biosensor devices that can be used on-site for patulin detection. 

Purpose: To develop and optimize a patulin electrochemical sensor based on the interaction of the mycotoxin with pyrrole

Methods: The assay was based on the formation of adducts from reacting the patulin sample with pyrrole monomer. The formation of adducts was visualized by a reduction in the oxidation peak caused by the electropolymerization of pyrrole onto the surface of a screen printed electrode. Optimization was performed in terms of pyrrole concentration, adduct formation time, pH and scan rate applied in voltammograms.

Results: The reaction of patulin with pyrrole formed an adduct that terminated polymer elongation during electropolymerization process. The observed decrease in oxidation peak correlates significantly to the concentration of patulin within the range (80ppb to 890ppb) with r² = 0.92.The detection limit is 45 ppb of patulin. The sensor response was optimal when the patulin and pyrrole were reacted for 45 mins or longer at pH 5.

Significance: The study has demonstrated proof-of-concept of an electrochemical sensor for the on-site detection of patulin. The sensor provides a further tool for inspectors and processors to minimize the introduction of patulin into the food chain.