Sensitive amperometric biosensor for the determination of biogenic and synthetic amines using pea seedlings amine oxidase: a novel approach for enzyme immobilisation

We prepared a new inorganic sorbent based on modified triazine (2-[4,6-bis (aminoethylamine)-1,3,5-triazine]-Silasorb; BAT-Silasorb) which binds pea s eedlings amine oxidase (PSAO) very tightly without loss of its catalytic ac tivity. This unique feature as well as the wide substrate specificity of PS AO was successfully utilised in the construction of an amperometric biosens or based on a carbon paste electrode for the fast and sensitive detection o f various amines at a formal potential 0 mV versus Ag/AgCl reference electr ode. The reaction layer of the biosensor is created by the direct immobilis ation of PSAO at the electrode surface via affinity carrier BAT-Silasorb. U sed arrangement facilitates a simple restoration of the inactive biosensor. An amperometric signal results from horseradish peroxidase catalysed reduc tion of H2O2, a secondary product of the oxidative deamination of amines, c atalysed by PSAO. The sensor was used for the basic characterisation of 55 biogenic and synthetic amines, from numerous mono-, di- and polyamines to v arious hydroxy-, thio-, benzyl- and aromatic derivatives in order to establ ish its suitability as a postcolumn detector. Its high sensitivity to putre scine 20.0 +/- 0.64 mA l(-1) per mol (636.9 +/- 2.03 mA l(-1) per mol per c m(2)), a limit of detection of 10 nmol l(-1) (determined with respect to a signal-to-noise ratio 3.1), a linear range of current response to 0.01-100 mu mol l(-1) concentration of substrate and good reproducibility all indica te that the sensor could be applied to future industrial and clinical analy ses. (C) 1999 Elsevier Science S.A. All rights reserved.