Evaluation of the Oxo‐bridged Dinuclear Ruthenium Ammine Complex as Redox Mediator in an Electrochemical Biosensor

The mediation of electron‐transfer by oxo‐bridged dinuclear ruthenium ammine [(bpy) 2 (NH 3 )Ru III ( µ ‐O)Ru III (NH 3 )(bpy) 2 ] 4+ for the oxidation of glucose was investigated by cyclic voltammetry. These ruthenium (III) complexes exhibit appropriate redox potentials of 0.131–0.09 V vs. SCE to act as electron‐transfer mediators. The plot of anodic current vs. the glucose concentration was linear in the concentration range between 2.52×10 −5 and 1.00×10 −4  mol L −1 . Moreover, the apparent Michaelis‐Menten kinetic ( K M app ) and the catalytic ( K cat ) constants were 8.757×10 −6  mol L −1 and 1,956 s −1 , respectively, demonstrating the efficiency of the ruthenium dinuclear oxo‐complex [(bpy) 2 (NH 3 )Ru III ( µ ‐O)Ru III (NH 3 )(bpy) 2 ] 4+ as mediator of redox electron‐transfer.