An efficient poly(pyrrole-viologen)-nitrite reductase biosensor for the mediated detection of nitrite

A biosensor for nitrite analytical determination was developed using a cytochrome c nitrite reductase (ccNiR) from Desulfovibrio desufuricans ATCC 27774 immobilized and electrically connected on a glassy carbon electrode by entrapment in an electrogencrated poly(pyrrole-viologen) matrix. The modified bioelectrode was studied by cyclic voltammetry and a catalytic current was observed in presence of nitrite. The linear range of the electrode response was 5.4-43.4 muM. The detection limit and the sensitivity were 5.4 muM and 1721 mA M-1 cm(-2), respectively. The K-M(app) value determined from the Lineweaver-Burk plot was 86 muM. The biosensor fully maintained its electroenzymatic activity towards nitrite after four days.. No catalytic response was observed in the presence of nitrate ions while interference from sulfites was considered negligible. Finally, the biosensor composition was optimized in term of monomer-enzyme ratio. (C) 2004 Elsevier B.V. All rights reserved.