Amperometric biosensor for the determination of histamine in fish samples

A bienzymatic biosensor employing diamine oxidase (DOx) and horseradish peroxidase (HRP) for the detection of histamine in fish samples has been developed and optimized in this work. These enzymes have been co-immobilized into a polysulfone/carbon nanotubes/ferrocene membrane by means of phase inversion technique onto screen-printed electrodes. The electrochemical measurements have been carried out in phosphate buffer solution at pH 8.0 in batch mode and low applied potential (-50 mV vs. Ag/AgCl, KCl 0.1 M) to minimize the interferences. Developed biosensor exhibits high sensitivity (1.9×10(7) nA(-1)), low limit of detection (1.7×10(-7) M), high storage stability and excellent reproducibility, obtaining a linear interval range from 3×10(-7) to 2×10(-5) M. Finally, applicability of the biosensor to the estimation of histamine content in different fish samples has been assessed; obtaining a good correlation between results obtained with the biosensor and those obtained with the reference method (ELISA) in case of sardines, mackerel and greater weever.