Dopamine sensor development based on the modification of glassy carbon electrode with β-cyclodextrin-poly(N-isopropylacrylamide)

Abstract

A stable electroactive film of β-cyclodextrin-poly(N-isopropylacrylamide) (CD-PNIPAM) was successfully prepared on a glassy carbon electrode (GCE) surface using an electroadsorption method for the determination of dopamine (DA). The electrochemical behavior of the fabricated sensor towards the catalytic oxidation of DA was investigated by a cyclic voltammetry (CV) method in pH 5.0 phosphate buffer solution. The CD-PNIPAM modified electrode exhibited a good electrocatalytic activity towards the oxidation of dopamine, and led to a significant decrease in the anodic overpotentials compared with bare GCE. Using a differential pulse voltammetry (DPV) method, the sensor gave a linear response to DA over the concentration range 0.1–60 μM with a detection limit (S/N = 3) of 3.34 × 10⁻⁸ M. The sensitivity of the sensor was 564.2 μA mM⁻¹. It was found that CD-PNIPAM possessed an inclusive property resulting from the β-CD in the structure of the polymer and could form an inclusion complex with dopamine molecules by hydrogen bonding interactions, which improved the detection limit and sensitivity for DA. The proposed sensor exhibits good sensitivity, selectivity and stability and has shown potential for the determination of DA in real samples.