A highly sensitive and selective method for dopamine detection based on poly (folic acid) film modified electrode

A highly sensitive and selective method based on poly (folic acid) modified electrode (PFA/CPE) to detect dopamine (DA) was established by electrochemical polymerization of folic acid on a carbon paste electrode (CPE). Subsequently, the morphologies of the electrode surface were observed by scanning electron microscopy (SEM) and the electrochemical behavior of DA at the PFA/CPE was studied. It was illustrated that the PFA/CPE had excellent electrocatalytic ability towards the oxidation of DA. The anodic peak current of DA was greatly enhanced at the PFA/CPE and the standard rate constant (ks) could be calculated to be 3.35 s(-1) Moreover, the interferences of ascorbic acid (AA) and uric acid (UA) on the determination of DA were eliminated. Consequently, the PFA/CPE was subjected to the determination of DA in the presence of AA and UA successfully. The linear responses were obtained over two concentration internals: 2.5 x 10(-8)-1.0 x 10(-6) mol L-1 and 1.0 x 10(-6)-1.0 x 10(-3) mol L-1 with a detection limit (S/N = 3) of 8 x 10(-9) mol L-1. With favorable selectivity and sensitivity, the present method has been applied to the determination of DA in dopamine hydrochloride injections. (C) 2012 Elsevier B.V. All rights reserved.