Ni(II)–quercetin complex modified multiwall carbon nanotube ionic liquid paste electrode and its electrocatalytic activity toward the oxidation of glucose

A modified electrode Ni(II)–Qu–MWCNT–IL–PE has been fabricated by electrodepositing Ni(II)–quercetin [Ni(II)–Qu] complex on the surface of multi-wall carbon nanotube ionic liquid paste electrode (MWCNT–IL–PE) in alkaline solution. The Ni(II)–Qu–MWCNT–IL–PE exhibits the characteristic of improved reversibility and enhanced current responses of the Ni(III)/Ni(II) couple compared with Ni(II)–Qu–MWCNT–PE. It also shows good electrocatalytic activity toward the oxidation of glucose. Kinetic parameters such as the electron transfer coefficient α, rate constant ks of the electrode reaction and the catalytic rate constant kcat of the catalytic reaction are determined. Moreover, the catalytic current presents linear dependence on the concentration of glucose from 5.0 μM to 2.8 mM, with a detection limit of 1.0 μM by amperometry. The modified electrode for glucose determination is of the property of simple preparation, good stability, fast response and high sensitivity.