聚钙羧酸修饰玻碳电极差分脉冲伏安法同时测定多巴胺和尿酸

Simultaneous Differential Pulse Voltammetric Determination of Dopamine and Uric Acid with Polycalconcarboxylic Acid Modified Glassy Carbon Electrode

采用电化学方法将钙羧酸(CCA)聚合修饰在玻碳电极(GCE)表面制备了聚钙羧酸指示剂修饰玻碳电极(PCCA/GCE),并用循环伏安法和交流阻抗法研究了电极的电化学性能。结果表明:在pH 6.0的磷酸盐缓冲溶液中,多巴胺(DA)和尿酸(UA)在聚钙羧酸修饰电极上的氧化峰得以分开,峰电位差为0.14V,据此提出了聚钙羧酸修饰电极差分脉冲伏安法同时测定多巴胺和尿酸的方法。DA和UA的浓度分别在5.0～43.8μmol.L-1和5.0～50.0μmol.L-1范围内与其氧化峰电流呈线性关系,检出限(3S/N)分别为0.2μmol.L-1和0.5μmol.L-1。方法可用于多巴胺注射液样品中DA和UA的测定,测定值的相对标准偏差(n=5)依次为2.43%和2.35%。

The modified electrode （PCCA/GCE） was prepared by electrochemical polymerization of calconcarboxylic acid （CCA） on the surface of glassy carbon electrode （C, CE）. The electrochemical property of the PCCA/GCE was studied by cyclic voltammetry and AC impedance method. It was found that in a PBS of pH 6.0, the oxidation peaks of dopamine （DA） and uric acid （UA） were completely separated, and the potential difference of the oxidation peaks attained to a value of 0. 14 V. Based on these findings, a selective method for simultaneous determination of DA and UA by differential pulse voltammetry was proposed. Linear relationships between values of oxidation peak current and concentration of DA and UA were obtained in the ranges of 5.0--43.8 μmol·L^-1 and 5.0 50. 0 fμmol·L^-1 , with their detection limits of 0. 2μmol·L^-1 and 0. 5μmlol·L^-1 respectively. The proposed method has been used in simultaneous determination of DA and UA in DA injections, giving values of RSD＇s n=5） of 2.43% for DA and 2.35%for UA.