Study on Electrochemical Behaviours and Diffusion Mechanism of Acetaminophen and Dopamine at Pre-Anodized Carbon Paste Electrode

A pre-anodized carbon paste electrode (PACPE) was fabricated and used to investigate the electrochemical behaviours of acetaminophen and dopamine. The results indicated that the voltammetric responses of acetaminophen and dopamine were considerably enhanced at PACPE in pH = 7.0 phosphate buffer solution. Furthermore, the diffusion mechanism of the influence on oxidation peak currents of acetaminophen and dopamine has been put forward. The driving force for the diffusion of acetaminophen and dopamine toward anode not only related to concentration diffusion but also involved with transport of H+ in the feed phase along a concentration gradient toward cathode. Under the optimized conditions in linear scan voltammetry technique, acetaminophen and dopamine gave linear response over the range of 2.0 x 10(-6)-5.0 x 10(-4) mol/L, 2.0 x 10(-6)-4.0 x 10(-4) mol/L, respectively. The detection limits (S/N = 11) were found to be 0.42 mu mol/L for acetaminophen and 0.21 mu mol/L for dopamine. The proposed method was successfully applied to the determination of acetaminophen and dopamine in commercial pharmaceutical samples.