Preparation of thiol-grafted poly(3,4-ethylenedioxythiophene)/yolk–shell carbon sphere/Au composites for the simultaneous detection of caffeic acid and levofloxacin

Abstract

As the void space can increase the effective surface area and the mesoporous shell ensures the fast transmission of electrons and ions, the yolk–shell-structured carbon spheres (YRFC) have been explored as electrode modification materials. Various hybrid nanocomposites of YRFC were studied for expanding their applications. In this work, a thiol-grafted poly(3,4-ethylenedioxythiophene)/resorcinol-formaldehyde yolk–shell carbon nanosphere/Au composite (PEDOTMeSH/YRFC/Au) was fabricated and used as the electrode material for the simultaneous electrochemical detection of caffeic acid (CA) and levofloxacin (LVF). The structure and morphology of the composite were investigated by UV-Vis and FTIR spectroscopy, XRD, XPS, SEM, TEM, EDS, and elemental mapping. The electrochemical performance of PEDOTMeSH/YRFC/Au was evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and the results were compared with those of YRFC/Au and PEDOT/YRFC/Au composites. The structural analysis revealed that PEDOTMeSH/YRFC/Au had a higher conjugation degree than the other composites. The morphological analysis indicated that the surface of YRFC was uniformly coated by PEDOTMeSH with well-dispersed Au NPs. The results of electrochemical studies showed that the limits of detection of the PEDOTMeSH/YRFC/Au composite electrodes were 0.014 μM and 0.018 μM, respectively, and the linear detection range was 0.02–320 μM for both CA and LVF.