Sensitive Determination of Nicotine on PolyNiTSPc Electrodeposited Glassy Carbon Electrode: Investigation of Reaction Mechanism

Abstract

In this paper, we report an electrochemical material for nicotine detection in aqueous solution by using glassy carbon electrode (GCE) electrodeposited with Nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (polyNiTSPc) in Tetra n-butil ammonium hydroxide (TnBAH) alkaline solution. The detection performance of the polyNiTSPc/GCE and the reaction mechanism of nicotine electro-oxidation process is investigated using Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) techniques in 0.1 M phosphate buffer solution (pH 7.5). The conductivity properties of the bare GCE and polyNiTSPc/GCE were analysed using Electrochemical impedance spectroscopy (EIS). The surface morphology of bare GCE and polyNiTSPc/GCE are characterized by Atomic Force Microscopy (AFM). PolyNiTSPc shows high catalytic activity for the electro-oxidation of nicotine, with the limit of detection at 146 nM nicotine. PolyNiTSPc/GCE can be used as a biosensor with very low detection limit for nicotine. Electrode process for nicotine oxidation is diffusion controlled, including irreversible one-electron transfer attributed to the nicotine/nicotine-Delta 1 ',(5 ')-iminium ion conversion on the polyNiTSPc coated electrode. Electrochemical measurements indicated that the polyNiTSPc against nicotine plays a similar role as CYP2A6 enzyme which catalyses the intermediate reaction product of nicotine-cotinine transformation in most mammalian species.