Straightforward method for the electrochemical identification of dopamine in the presence of uric acid and ascorbic acid

A few-layer graphene/Pt (FGP) electrode and a novel electrochemical technique were used in determining dopamine and simultaneously detecting uric acid (UA), ascorbic acid (AA), and dopamine (DA) in a buffered phosphate-saline solution at pH 7.4. The FGP electrode effectively separated the oxidation peaks of UA, DA, and AA in the positive scan. Interestingly, during the negative scan, the FGP electrode selectively responded to DA while showing negligible response to UA and AA, thus allowing the accurate quantification of small amounts of DA in the presence of considerable UA and AA interferences. The sensors for AA, DA, and UA exhibited successful detection in the positive scan. The linear ranges were 10-1800 (AA), 1-300 (DA), and 5-800 (UA) mu M, the sensitivity was 109.27 (AA), 754.19 (DA), and 493.03 (UA) mu A cm-2 mM-1, and the detection limits were 4.2 mu M (AA), 0.42 mu M (DA), and 2.2 mu M (UA). Furthermore, DA quantification was achieved in the negative scan, demonstrating a linear range of 1-100 mu M, sensitivity of 2235.7 mu A cm-2 mM-1, and detection limit of 0.14 mu M. This study presents a novel and efficient electrochemical technique for the rapid and straightforward detection of dopamine.