Ferraz Bruno Regis Lyrio, Leite Fernando Roberto Figueiredo, Malagutti Andréa Renata
Department of Pharmacy, Federal University of Vales do Jequitinhonha e Mucuri, MGT 367 Highway - Km 583, Diamantina, MG, Brazil.
Department of Pharmacy, Federal University of Vales do Jequitinhonha e Mucuri, MGT 367 Highway - Km 583, Diamantina, MG, Brazil.
Talanta. 2016 Jul 1;154:197-207. doi: 10.1016/j.talanta.2016.03.058. Epub 2016 Mar 22.
A selective, simple and rapid square wave voltammetry method, based on electropolymerization of l-cysteine (poly(l-Cys)) on a glassy carbon electrode (GCE), was developed in this study for simultaneous determination of ethionamide and pyrazinamide. Electroanalytical and electrochemical properties of the poly(l-Cys)/GCE were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). The cyclic voltammetry studies revealed an remarkable electrocatalytic activity of poly(l-Cys)/GCE on ethionamide and pyrazinamide at pH 1.0. The best potential separation between the reduction peaks of the drugs in a mixed solution was found to be 0.14V. It was also found that pyrazinamide exhibits a reversible wave with Epc and Epa at -404mV and -347mV (versus EAg/AgCl), respectively, while ethionamide presents an irreversible reduction peak at Epc=-536mV. The optimized calibration curves for simultaneous determination of ethionamide and pyrazinamide exhibited good and high linear responses within the concentration range 2.38-248.0µmolL(-1) and 0.476-51.2µmolL(-1), respectively. The limit of detection was found to be 0.531µmolL(-1) for ethionamide and 0.113µmolL(-1) for pyrazinamide. The poly(l-Cys)/GCE-based square wave voltammetry method was successfully used to determine ethionamide and pyrazinamide in human urine and blood serum.
本研究开发了一种基于在玻碳电极（GCE）上对L-半胱氨酸（聚L-半胱氨酸）进行电聚合的选择性、简单且快速的方波伏安法，用于同时测定乙硫异烟胺和吡嗪酰胺。通过循环伏安法（CV）、方波伏安法（SWV）、电化学阻抗谱（EIS）和扫描电化学显微镜（SECM）研究了聚L-半胱氨酸/GCE的电分析和电化学性质。循环伏安法研究表明，在pH 1.0时，聚L-半胱氨酸/GCE对乙硫异烟胺和吡嗪酰胺具有显著的电催化活性。发现混合溶液中药物还原峰之间的最佳电位分离为0.14V。还发现吡嗪酰胺在-404mV和-347mV（相对于Ag/AgCl）处分别呈现Epc和Epa的可逆波，而乙硫异烟胺在Epc = -536mV处呈现不可逆还原峰。同时测定乙硫异烟胺和吡嗪酰胺的优化校准曲线在浓度范围分别为2.38 - 248.0µmolL(-1)和0.476 - 51.2µmolL(-1)内表现出良好且高度的线性响应。乙硫异烟胺的检测限为0.531µmolL(-1)，吡嗪酰胺的检测限为0.113µmolL(-1)。基于聚L-半胱氨酸/GCE的方波伏安法成功用于测定人尿液和血清中的乙硫异烟胺和吡嗪酰胺。
