抗坏血酸共存下用聚氨基-β-环糊精修饰电极测定多巴胺

Determination of dopamine in the presence of ascorbic acid at polymeric amino-β-cyclodextrine modified glassy carbon electrode

采用循环伏安法制备了6-氨基-6-脱氧-β-环糊精的聚合物膜（PACD）修饰电极，研究了该修饰电极在抗坏血酸（AA）共存条件下对多巴胺（DA）的电化学行为．结果表明其能有效消除抗坏血酸的干扰，将多巴胺和抗坏血酸二者在裸电极上的完全重叠的单氧化峰分开成为两个完全独立的氧化峰，差分脉冲伏安（DPV）图上峰间距E428mV，在pH6．5的磷酸盐缓冲溶液中，氧化峰电流与多巴胺浓度在3．5×10^-6～5．0×10^-4mol／L范围内成良好的线性关系，相关系数达0.9905，检出限为2．0×10^-7mol／L。可用于在AA的共存下的多巴胺样品的选择性测定。

A polymeric of 6^A-amino-6^A-deoxy- β -cyclodextrin （PACD） thin film-modified glassy carbon electrode was prepared by electropolymerization, its electrochemical behavior towards the oxidation of DA and AA was investigated, the results showed that PACD modified electrode not only can improve the electrochemical behaviors of DA and AA, but also can resolve the mixed voltammetric response of DA and AA at PACD modified electrode into two well-defined voltammetric peaks, in pH 6.5 phosphate buffer solution,The separation between the two peak potentials were 428mV in differential pulse voltammetry （DPV） respectively, the peak current of oxidation was proportional to the concentration of DA and a good linear relation from 3.5 × 10^-6 to 5.0 × 10^-4mol/L （ r= 0.9905 ） with a detection limit of 2.0 ×10^-7mol/L was obtained. The methods were large enough for the determination of DA in the presence of AA.