He Jian-Bo, Jin Guan-Ping, Chen Qun-Zhi, Wang Yan
School of Chemical Engineering, Hefei University of Technology, Hefei 230009, PR China.
Anal Chim Acta. 2007 Mar 7;585(2):337-43. doi: 10.1016/j.aca.2007.01.004. Epub 2007 Jan 17.
The present work reports a quercetin-modified wax-impregnated graphite electrode (Qu/WGE) prepared through an electrochemical oxidation procedure in quercetin-containing phosphate buffer solution (PBS), for the purpose of detecting uric acid (UA) in the presence of ascorbic acid (AA). During modification quercetin was oxidized to the corresponding quinonic structure, and in the blank buffer solution the electrodeposited film exhibits a voltammetric response anticipated for the surface-immobilized quercetin. Retarding effect of the film towards the reaction of anionic species was found; therefore the pH of sample solutions was selected to ensure the analyte in molecular form. At suitable pHs the Qu/WGE shows excellent electrocatalytic effect towards the oxidation of both AA and UA, and separates the voltammetric signal of UA from AA by about 280 mV, allowing simultaneous detection of these two species. A linear relation between the peak current and concentration was obtained for UA in the range of 1-50 microM in the presence of 0.5 mM AA, with a detection limit 1.0 microM (S/N=3). This sensor was stable, reproducible and outstanding for long-term use.
本研究报告了一种槲皮素修饰的蜡浸石墨电极(Qu/WGE),该电极通过在含槲皮素的磷酸盐缓冲溶液(PBS)中进行电化学氧化制备,用于在抗坏血酸(AA)存在的情况下检测尿酸(UA)。在修饰过程中,槲皮素被氧化为相应的醌结构,并且在空白缓冲溶液中,电沉积膜表现出表面固定化槲皮素预期的伏安响应。发现该膜对阴离子物种的反应有阻碍作用;因此选择样品溶液的pH值以确保分析物呈分子形式。在合适的pH值下,Qu/WGE对AA和UA的氧化均表现出优异的电催化作用,并将UA的伏安信号与AA的伏安信号分离约280 mV,从而能够同时检测这两种物质。在存在0.5 mM AA的情况下,UA在1-50 microM范围内的峰电流与浓度之间呈线性关系,检测限为1.0 microM(S/N=3)。该传感器稳定、可重现,长期使用性能优异。