Evaluation of substituted-1,10-phenanthroline complexes of osmium as mediator for glucose oxidase of Aspergillus Niger Original Research Article

A series of novel substituted-1,10-phenanthroline complexes of osmium and ruthenium have been synthesized and characterized electrochemically with respect to their ability to act as electron transfer mediator for glucose oxidase. These complexes exhibit high second-order rate constants for reduced glucose oxidase in the order of 106–107 M−1 s−1. The complexes bearing electron-donating substituents give a significantly higher rate constant with glucose oxidase and lower redox potential than those bearing electron-accepting substituents. 4,7-Dimethy-1,10-phenanthroline and 3,4,7,8-tetramethy-1,10-phenanthroline complexes of osmium have been characterized in details as mediator for glucose oxidase. The application of the family of mediators in amperometric biosensors seems feasible.