A sandwich-structured, layered CoTMPyP/Sr2Nb3O10 nanocomposite for simultaneous voltammetric determination of dopamine and ascorbic acid

Abstract

As a vehicle for simultaneous voltammetric determination of dopamine and ascorbic acid, a sandwich-structured, layered CoTMPyP/Sr2Nb3O10 nanocomposite was synthesised via exfoliation/restacking. Negatively charged Sr2Nb3O10 nanosheets were assembled with positively charged 5,10,15,20-tetrakis (N-methylpyridinium-4-yl) porphyrinato cobalt (CoTMPyP). The structure and morphology of CoTMPyP/Sr2Nb3O10 nanocomposite were characterised using XRD (X-ray diffraction), Scanning electronmicroscope (SEM), Transmission electron microscope (TEM), Energy dispersive spectrometer analysis (EDS) and Fourier transform infrared spectrometer (FTIR). The CoTMPyP/Sr2Nb3O10 nanocomposite has a layered structure with the CoTMPyP cations inserted into the interlayer spacing of the Sr2Nb3O10 nanosheets with an angle of inclination of 51.5°. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) results show that dopamine (DA) and ascorbic acid (AA) could be detected selectively and sensitively at CoTMPyP/Sr2Nb3O10/GCE (glassy carbon electrode) with peak-to-peak separation of 263 mV in the N2-saturated phosphate buffer saline (PBS, pH = 6). Electrochemical sensing towards DA and AA on CoTMPyP/Sr2Nb3O10 displays low respective detection limits of 7.6 μM and 10.6 μM, each in a wide linear range of 0.02–1.62 mM and 0.05–3.25 mM, respectively.