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

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 degrees. 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 N-2-saturated phosphate buffer saline (PBS, pH = 6). Electrochemical sensing towards DA and AA on CoTMPyP/Sr2Nb3O10 displays low respective detection limits of 7.6 mu M and 10.6 mu M, each in a wide linear range of 0.02-1.62 mM and 0.05-3.25 mM, respectively.