聚L-苏氨酸修饰电极对多巴胺和肾上腺素的电催化氧化

利用循环伏安法将L-苏氨酸聚合修饰在玻碳电极表面, 制成聚L-苏氨酸修饰电极. 实验表明, 该电极对多巴胺和肾上腺素都有较好的催化氧化效果. 运用循环伏安法详细研究了修饰电极的电化学性质. 在pH 2.5的磷酸盐缓冲溶液(PBS)中, 肾上腺素的电子传递系数为0.51, 表观反应速率常数为1.33 s-1; 在pH 7.5的PBS中, 多巴胺在电极上产生一对氧化还原峰, 多巴胺在电极上的电子传递系数为0.60, 表观反应速率常数为0.92 s-1. 该修饰电极对多巴胺和肾上腺素能够进行同时测定, 还原峰电流与多巴胺和肾上腺素浓度分别在1.0×10-6-5.0×10-4 mol·L-1和3.0×10-6-1.0×10-4 mol·L-1范围内呈现良好的线性关系.

Electrocatalytical Oxidation of Dopamine and Epinephrine at Poly(L-threonine) Modified Electrode

A poly(L-threonine) modified electrode (PLTE) was fabricated by electrochemical immobilization of L-threonine on a glassy carbon electrode (GCE). The poly(L-threonine) layer exhibited superior electrocatalytic activity towards both dopamine (DA) and epinephrine (EP). The electrochemical behaviors of the modified electrode were explored in detail with cyclic voltammetry. The apparent electron transfer coefficient and standard rate constant were calculated to be 0.51 and 1.33 s-1, respectively, for the oxidation of EP in pH 2.5 phosphate buffer solution (PBS). The modified electrode exhibited a pair of redox peaks for the oxidation of DA in pH 7.5 PBS, the apparent electron transfer coefficient and standard rate constant were calculated to be 0.60 and 0.92 s-1, respectively. The cathodic peak currents were proportional to the concentration of DA and EP in the range of 1.0×10-6-5.0×10-4 mol·L-1 and 3.0×10-6-1.0×10-4 mol·L-1, respectively. This method was successfully applied for simultaneous determination of DA and EP.