Selective response of dopamine on 3-thienylphosphonic acid modified gold electrode with high antifouling capability and long-term stability.

Abstract In this work, an Au electrode modified with self-assembled monolayers (SAMs) of 3-thienylphosphonic acid (TPA) was used as a novel functional interface to selectively sense dopamine (DA) in the presence of excess ascorbic acid (AA). Ellipsometry, X-ray photoelectron spectroscopic (XPS) and electrochemical measurements proved the immobilization of TPA on the gold surface. Interestingly, the Au electrode modified with TPA substantially improved the antifouling and renewal capabilities towards the oxidation of dopamine (DA) after 15 days of storage in undeoxygenated phosphate buffer solution (PBS pH 7.4). Moreover, the TPA-SAMs modified Au electrode could afford a selective electrochemical response for the DA oxidation in the presence of ascorbic acid (AA). Based on this result, a high sensitive detection limit of 2.0 × 10−7 M for DA could be obtained in the presence of high concentration of AA. Graphical abstract Unlabelled Image Highlights • Modification of Au electrodes with TPA are obtained by self-assembly method. • TPA plays an important role for the determination of DA. • DA can be determined in the presence of AA at TPA/Au electrode. • A high sensitive detection limit for DA can be obtained by TPA/Au electrode. [ABSTRACT FROM AUTHOR]