Study on electrochemical behaviors and the reaction mechanisms of dopamine and epinephrine at the pre-anodized inlaying ultrathin carbon paste electrode with nichrome as a substrate

In this paper, nichrome was adopted as a substrate, to fabricate the pre-anodized inlaying ultrathin carbon paste electrode (PAIUCPE). The electrochemical behaviors of dopamine (DA) and epinephrine (EP) at the electrode were investigated by cyclic voltammetry (CV). The reaction mechanisms of DA and EP have also been put forward. It was found that the electrode showed an excellent electrochemical behavior for electrode reaction of DA and EP. The cathodic potential difference of DA and EP was about 370 mV and the simultaneous determination of DA and EP was achieved based on it. The reduction peak current was proportional to the DA and EP concentrations in the range of 8.0 × 10− 7–3.0 × 10− 4 M and 2.0 × 10− 6–1.5 × 10− 4 M with the detection limits of 1.70 × 10− 7 M and 3.27 × 10− 7 M, respectively. Because the oxidation of ascorbic acid (AA) is an irreversible reaction at the PAIUCPE, the interferences of AA for determining DA and EP were eliminated. The method has been successfully applied to the determination of DA and EP in hydrochloride injection with satisfactory results.

The electrochemical behaviors of DA (1) and EP (2) at the PAIUCPE (curve d) were stronger than the IUCPE (curve c). The cathodic potential difference (∆Ep) of DA and EP was about 370 mV at the PAIUCPE and the simultaneous determination of DA and EP was achieved based on it.Figure optionsDownload as PowerPoint slideHighlights
► At the PAIUCPE, the electrochemical behaviors of DA and EP are investigated by CV.
► The cathodic potential difference (∆Ep) of DA and EP is about 370 mV.
► The mechanism of the effect of pH on peak current and peak potential is discussed.
► The simultaneous determination of DA and EP in PBS (pH 7.00) is achieved.