Differential pulse voltammetric determination of dopamine with the coexistence of ascorbic acid on boron-doped diamond surface

Electrochemical determination of dopamine (DA) in the presence of ascorbic acid (AA) was achieved on boron-doped diamond (BDD) film electrode by differential pulse voltammetry. The experimental results indicated that the oxidative peaks of DA and AA could be separated completely on anodically-treated (BDD) electrode without further modification, although these two peaks can not be separated on glassy carbon electrode. The peak separation of DA and AA was developed to be 0.44 V. High sensitivity was obtained to determine DA selectively with the coexisting of a large excess of AA in acidic media by DPV. The detection limit of DA was achieved to be 1.1 × 10^-6 M in the presence of AA with the concentration of 200 times more than DA. This technique was also applied to the determination of DA in real samples.