Electrochemical behavior of dopamine at dodecyl benzenesulfonate self-assembled monolayers modified electrode and its application

Sodium dodecyl benzenesulfonate (SDBS) self-assembled monolayers in situmodified electrode (SDBS/CPE) was prepared. The electrochemical behaviors of dopamine (DA) on SDBS/CPE were studied. Electrochemical behaviors and kinetic parameters of DA were investigated at SDBS/CPE by cyclic voltammetry (CV), chronoamperometry (CA) and chronocoulometry (CC). The changes of the oxidation peak currents with concentration of DA were examined by square wave voltametry (SWV). The difference of peak potential at CPB/CPE was less than 149 mV comparing with that at CPE. The charge transfer coefficient α, diffusion coefficient D and the apparent reaction rate constant K_f are 0.61, 3.6×10^-5 cm²·s^-1 and 4.2×10^-3 cm·s^-1, respectively. The oxidation peak currents of DA versus its concentration have a good linear relationship in the concentration range of 2.0×10^-6-1.0×10^-3 mol·L^-1 with the correlation coefficient of 0.997 9 and the detection limit of 9.0×10^-7 mol·L^-1 by square wave voltammetry (SWV) response. The modified electrode showed an excellent electrocatalytic activity for the DA electrochemical oxidation. The method can be applied in the determination of DA in injection samples with the satisfactory results.