Amperometric Determination of Dopamine Using Activated Screen-Printed Carbon Electrodes

Abstract

In this paper, we determined dopamine using screen-printed carbon electrodes (SPCEs) which was activated by 0.1 mol L−1 NaOH solution deposited on the electrode to improve the capabilities of detection. Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of dopamine. Cyclic voltammetry studies indicated that electrochemical oxidation of dopamine at the surface of SPCEs was decided by pH value. Different pulse voltammetry for dopamine oxidation at the SPCEs yielded a well-defined oxidation peak at 0.2 V in 0.1 mol L−1 phosphate buffer (pH 5.0). The proposed electrodes showed good selectivity for dopamine and a good linear relationship between dopamine concentration and oxidation current was obtained within the range of 2.0 × 10−7 mol L−1–300.0 × 10−6 mol L−1 with a detection limit of 6.7 × 10−8 mol L−1 (S/N = 3). In addition, the results showed that the precision in terms of reproducibility was 2.8% in the case of the activated SPCEs. The recovery rates of this technology were 95.40 to 103.4% with a relative standard deviation (RSD) was 2.7%–4.6%, indicating that this method can completely be used for detecting the practical dopamine injection sample.