Bioelectrochemical determination at histamine dehydrogenase-based electrodes

Abstract

Histamine dehydrogenase (HmDH) from Nocardioides simplex was used in constructing mediated bioelectrochemical systems for histamine oxidation using Os complexes as mediators. Amperometric histamine sensor was prepared by immobilizing a mixture of HmDH and a mediator, poly(1-vinylimidazole) complexed with [Os(2,2′-dipyridylamine)2Cl], with a crosslinker, poly(ethylene glycol) diglycidyl ether on a glassy carbon electrode. The electrode responded linearly to histamine over the range from 2 to 30 μmol dm-3, became free from the substrate inhibition observed in solution, and was almost insensitive to ascorbate at pH 7.0. On the other hand, the charge in coulometry using carbon felt electrodes was proportional to the histamine amount over the range from 0.1 to 5 nmol and the slope indicates a 4-electron oxidation (2-electron in the enzyme reaction and 2-electron in follow-up electrochemical reaction).