Synthesis and characterization of benzenesulfonate derivatives doped poly(3,4-ethylenedioxythiophene) films and their application in electrocatalysis

The dopant anion in poly(3,4-ethylenedioxythiophene) (PEDOT) plays a critical role in determining the physical and chemical properties of these conducting polymers. In this paper, six kinds of benzenesulfonate derivatives, including benzenesulfonate (BS), p-methylbenzene-sulfonate (p-MBS), p-aminobenzenesulfonate (p-ABS), p-hydroxybenzene-sulfonate (p-HBS), m-carboxylbenzenesulfonate (m-CBS) and m-nitrobenzenesulfonate (m-NBS) were used to dope PEDOT via a facile electrochemical deposition strategy. The presence of the dopants in the conducting polymer matrix was verified by Fourier transform infrared spectroscopy (FTIR) and ultraviolet spectrum (UV/vis) and the morphologies of the resulting benzenesulfonate derivatives doped PEDOT films were analyzed by scanning electron microscopy (SEM). The electrocatalytic activities of these doped PEDOT films toward VB2, VB9 and VC were investigated by cyclic voltammetry (CV). Among them, the PEDOT/p-ABS− film shows a higher catalytic peak currents, which might be ascribed to the large surface area of nanostructured PEDOT/p-ABS− film, and the strong interaction between NH group doped in PEDOT/p-ABS− film and VB2, VB9 and VC via hydrogen bonding. Then the PEDOT/p-ABS− film modified glass carbon electrode (PEDOT/p-ABS−/GCE) was utilized as an electrochemical sensor for the simultaneous detection of these vitamins, and the linear ranges for VB2, VB9 and VC are 0.05–200 μM, 0.5–1000 μM and 1–1500 μM with limits of detection of 0.015 μM, 0.12 μM and 0.46 μM, respectively, (S/N = 3). Moreover, the modified electrode was successfully employed for the determination of VB2, VB9 and VC in human blood plasma with satisfactory results.