Non-enzymatic Sensing of Glucose Using Glassy Carbon Electrode Modified with Organometallic Complex of Nickel

A glassy carbon electrode(GCE) modified with organometallic complex of nickel: (S)-[O-[(N-benzylpropyl)amino](phenyl)methyleneiminoacetate(2-)-N,N',N ''-nickel(II) (Ni-(S)BPB-Gly, irreversibly adsorbed on the electrode surface was investigated. The modified electrode shows an electrochemically reversible reaction due to a Ni(II)/Ni(III) redox couple and electrocatalytic activity toward glucose oxidation in alkaline solution. The electrochemical behaviors of the GCE modified with a redox film were investigated by cyclic voltammetry and chronoamperometry techniques. According to the voltammetric studies, the increase in the anodic peak current and subsequent decrease in the corresponding cathodic current, glucose was oxidized on the modified electrode surface via an electrocatalytic mechanism. The amperometric results indicate that glucose oxidation current response increases with increasing glucose concentrations. When this is high enough, the current tends to be stable, showing the characteristics of Michaelis-Menten kinetics. The Michaelis-Menten constant (KM) and the maximum current density (i(max)) were 2.3 mM and 4.6 mA cm(-2), respectively. The activation energy of the electrocatalytic reaction was estimated to be 42.1 kJ mol(-1).