Electrochemical biosensors for biogenic amines: a comparison between different approaches

Diamine oxidase (DAO) has been examined in order to obtain a sensor for biogenic amines; the enzyme was immobilised directly on the surface of a platinum electrode, poised at +700 mV vs. Ag/AgCl, or immobilised on glass beads in a small reactor (diameter 2 mm, length 40 mm) and included in a flow-injection analysis assembly. Moreover, it was coupled with horseradish peroxidase coimmobilised and coupled with a glassy carbon electrode using ferrocene monocarboxylic acid as mediator dissolved in the carrier stream. Low detection limits were obtained in all cases with some differences; the selectivity was quite similar in the different assemblies. Moreover, we showed that selectivity can be changed using DAO, obtained from different starting materials not commercially available such as pea (Cicer arietinum).