Electrochemical studies of two diphenols isomers at graphene nanosheet-poly(4-vinyl pyridine) composite modified electrode

摘要

A voltammetric sensor for hydroquinone (HQ) and catechol (CC) was developed. This was realized by modifying a glassy carbon electrode with composite film of graphene nanosheet and poly(4-vinylpyridine) (GR-P4VP/GCE). The smaller peak potential separation (ΔE_P) of the GR-P4VP/GCE indicates the electrode process is very reversible as a result of increase in kinetics of electron transfer as and when P4VP was present in the modified electrode as compared to the GR/GCE and bare GCE. The proposed electrode has displayed a synergistic effect of P4VP and GR on the electrocatalytic oxidation of CC and HQ in sodium sulphate buffer solution (pH 2.5). The anodic peak potential, E_pa, of both were clearly resolved in either cyclic voltammetry or differential pulse voltammetry which made simultaneous determination of both compounds possible. The GR-P4VP/GCE has exhibited excellent sensitivities in the measurement of HQ and CC with detection limits of 8.1 nM and 26 nM, respectively. The GR-P4VP/GCE developed was not interfered by traditional interferences, viz. phenol, nitrophenol, aminophenols, bisphenol A and chlorophenols. The GR-P4VP/GCE was successfully applied for simultaneous detection of spikes HQ and CC in tap water and lake water with encouraging results.