Highly Selective Dopamine Determination by Using Carboxymethylated β‐Cyclodextrin Polymer Film Modified Electrode

Abstract

Abstract A highly selective and sensitive electrochemical sensor modified with carboxymethylated β‐cyclodextrin (CM‐β‐CDP) polymer film was fabricated for the determination of dopamine (DA) in the presence of ascorbic acid (AA). The electrochemical behavior of DA and AA at the chemically modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry. The response mechanism of CM‐β‐CDP film for DA was based on the combination of electrostatic and inclusion interaction of CM‐β‐CDP for DA, which was distinguished from the response mechanism of the charged polymer film modified electrode that only relied upon the electrostatic interaction between charged polymer film and DA (or AA) to realize the separation of overlapping peak potential of DA and AA. The CM‐β‐CDP film showed preferable analytical performance characteristics in catalytic oxidation of DA compared with the β‐CDP polymer film. Under optimized conditions, it was feasible for the electrode modified with the CM‐β‐CDP film to selectively determine DA in the presence of a large excess of AA. A linear calibration plot was obtained over the range 0.8–60 µM with a sensitivity of 65 nA/µM and a detection limit (signal/noise (S/N) = 3) of 0.2 µM in the presence of 1.0 mM AA. This electrochemical sensor showed excellent sensitivity, repeatability, stability, and recovery for the determination of DA. The interference of AA with the determination of DA could be efficiently eliminated.