关键词: 修饰电极, 柠檬酸, 多巴胺, 肾上腺素

Abstract: The citric acid modified glassy carbon electrode (CA/GC) was prepared by potentiostatic technique and was used for detections of dopamine (DA), epinephrine (EP), and their mixtures by differential pulse voltammetry (DPV). The modified electrode shows the enhanced sensitivity and excellent electrochemical discrimination to DA and EP. The cathodic potential difference between DA and EP was about 380 mV, while no cathodic reduction of ascorbic acid (AA) was observed because the oxidation of AA is an irreversible reaction at the sensor. As a result, DA and EP could be determined simultaneously with the interferences of high concentrations of AA being eliminated. The reduction peak currents obtained in the phosphate buffer solutions at pH=6.0 were linearly dependent on the DA and EP concentrations in the ranges of 1.0×10-6～6.0×10-5 mol?L-1 and 2.0×10-6～6.0×10-5 mol?L-1, respectively. The proposed method showed potential applications in the simultaneous detections of DA and EP in injections.

Key words: modified electrode, citric acid, dopamine, epinephrine