A novel N,N′-[1,1′-Dithiobis(phenyl)] bis(salicylaldimine) self-assembled gold electrode for determination of dopamine in the presence of high concentration of ascorbic acid

N,N′-[1,1′-Dithiobis(phenyl)] bis(salicylaldimine) (DTPS) self-assembled monolayer has been fabricated on a bare gold electrode (Au electrode) as a novel sensor for determination of dopamine. The characterization of Au DTPS self-assembled monolayer modified electrode (DTPS SAM-ME) was investigated by cyclic voltammetry and ac impedance spectroscopy using the [Fe(CN)6]−3/−4 redox couple. The electroanalytical determination of dopamine was carried out in pH 6.0 0.1 mol L−1 phosphate buffer solution using differential pulse voltammetry. The diffusion coefficient of dopamine was calculated by chronocoulometry in pH 6.0 phosphate buffer solution to be 6.6 × 10−5 cm2 s−1. A calibration curve was obtained for dopamine in a linear range of 8.0 × 10−7 to 1.3 × 10−4 mol L−1 in the presence of high concentration of ascorbic acid. Selective detection was realized in elimination of ascorbic acid response on the DTPS SAM-ME. The detection limit for dopamine was found to be 3.0 × 10−8 mol L−1. The modified electrode showed acceptable selectivity, stability and anti-fouling properties. The results indicated that the DTPS SAM-ME could be employed for the determination of dopamine in pharmaceutical formulations and plasma samples. The lack of a voltammetric response for the oxidation of uric acid demonstrated that the human urine could be used for dopamine recovery tests with adequate selectivity and precision.