A biosensor consisting of Ca2Nb3O10− substrates and functional molecule manganese porphyrins (MnTMPyP) utilized for the determinations of nitrite

Abstract

As functional molecules, the cationic manganese (III) tetrakis-5, 10, 15, 20-(N-methyl-4-pyridyl) porphyrins (MnTMPyP) were used to assemble with the exfoliated Ca2Nb3O[Formula: see text] nanosheets, which were obtained via treating the acidified compounds HCa2Nb3O[Formula: see text] of perovskite composites KCa2Nb3O[Formula: see text] with the tetrabutyl ammonium hydroxide (TBA[Formula: see text]OH[Formula: see text] aqueous solution. Several analytic techniques, such as XRD, SEM, TEM, FT-IR, UV-Vis, were employed to investigate the morphology and structure of KCa2Nb3O[Formula: see text], HCa2Nb3O[Formula: see text] and intercalation nanocomposites MnTMPyP/Ca2Nb3O[Formula: see text]. The stability and uniformity of the obtained Ca2Nb3O[Formula: see text] nanosheets colloidal dispersion were proved by the surface charge of [Formula: see text][Formula: see text]mV, which was obtained by a Zetasizer Nano instrument. Meanwhile, the electrochemical properties of MnTMPyP/Ca2Nb3O[Formula: see text] nanocomposites modified glass carbon electrode (GCE) was tested by using the cyclic voltammetry (CV) measurements and the differential pulse voltammetry (DPV) measurements. Results show that the intercalation nanocomposites have a good electrocatalysis towards oxidation of nitrite with a peak potential decrease from 1.125[Formula: see text]V to 0.916[Formula: see text]V. There is a good linear correlation between the reduction peak current and the square root of the scan rate, indicating a diffusion controlled process. In the end, an estimate of the detection limit was [Formula: see text][Formula: see text]M at a signal-to-noise ratio of 3.0 with a concentration range of [Formula: see text][Formula: see text]M to [Formula: see text][Formula: see text]M.