Determination of biogenic amines with an electrochemical biosensor and its application to salted anchovies

This paper describes the assembling and optimization of an electrochemical biosensor for the determination of biogenic amines (putrescine, cadaverine, histamine, tyramine, spermidine, spermine, tryptamine) commonly present in food products, and its application to salted anchovy samples. Variations of the amine content in anchovies during ripening time were measured both with the biosensor and ion chromatography with integrated pulsed amperometric detection (IC-IPAD). The probe is based on a platinum electrode which senses the hydrogen peroxide produced by the reaction catalysed by the enzyme diamine oxidase (DAO), purified from commercial seeds of cicer and immobilized on the electrode surface. Parameters such as enzyme immobilization and pH have been studied and optimised in order to obtain similar sensitivity for all the amines tested. The immobilization of the enzyme on a nylon-net membrane, using glutaraldehyde as cross-linking agent, and phosphate buffer at pH 8.0 were selected. The detection limit was 5 x 10(-7) mol litre(-1). The linear range common to the amines tested was observed from 1 x 10(-6) to 5 x 10(-5) mol litre(-1). The effect of potentially interfering compounds was also evaluated. Underivatized biogenic amines such as putrescine, cadaverine, histamine, tyramine and spermidine were also detected with the IC-IPAD method. Changes in the concentration of biogenic amine content in salted anchovy samples, measured with the biosensor and IC-IPAD methods, exhibited the same trend and demonstrated that the biosensor is a useful tool to monitor the variation of the total amine content in fish during storage. (C) 1998 Elsevier Science Ltd. All rights reserved.