Amine Oxidase Based Amperometric Biosensors forHistamine Detection

This work reports on the development and optimization of amperometric biosensors based on the enzyme amine oxidase (AO) for the detection of histamine, a well-known biomarker for food freshness. Biosensor characteristics were evaluated in a flow injection (FI) analysis line, operated at +200 mV (vs. Ag/AgCl/0.1 M KCl). Two different biosensor designs were considered, one based on adsorbed AO on graphite electrodes, the detection being based on a direct electron transfer (DET) mechanism, whereas the second one based on an Os-bipyridine modified redox polymer using a mediated electron transfer (MET) pathway. Both electrode designs were able to detect histamine in µM range, however, the [osmium(4,4′-dimethylbipyridine)2Cl]+/2+ complexed with poly(1-vinylimidazole) (PVI13-dmeOs) based electrodes showed superior characteristics with regard to stability, selectivity and linear range. These electrodes were characterized by a detection limit of 2.2 µM (calculated as three times the signal-to-noise ratio), a sensitivity of 6.8 mA M–1 cm–2, a linear range of 10–200 µM, and an operational stability of 20 % response loss during 8 h of continuous operation at a sample throughput of 30 injections h–1.