Simultaneous and sensitive detection of ascorbic acid and uric acid using a novel MnTMPyP/LaTa2O7 nanocomposite modified glassy carbon electrode

Abstract

A novel nanocomposite MnTMPyP/LaTa2O7 was synthesized via intercalation of [5, 10, 15, 20-tetrakis (N-methylpyridinium-4-yl) porphyrinato manganese (III) (MnTMPyP) into the laminar structure of RbLaTa2O7 using an ion exchange method. An electrochemical sensor utilizing a MnTMPyP/LaTa2O7 modified glassy carbon electrode (GCE) was employed for the simultaneous detection of ascorbic acid (AA) and uric acid (UA). X-ray diffractometry, Fourier infrared spectroscopy, and transmission electron microscopy were utilized to characterize the structure in this experiment. Differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were employed to analyze the electrochemical properties. The MnTMPyP/LaTa2O7/GCE demonstrated a larger electrochemically active area (0.106 cm2), lower charge transfer resistance (43.1 Ω), and enhanced catalytic activity compared to single-component modified electrodes (RbLaTa2O7/GCE, bare/GCE). The detection limits, within the concentration ranges of 1.25–40.41 μM for AA and 0.62–11.81 μM for UA (S/N = 3), were estimated to be 0.37 μM and 0.44 μM, respectively. MnTMPyP/LaTa2O7/GCE also exhibits excellent stability, reproducibility, and anti-interference compared to previous literatures. Furthermore, the performance of MnTMPyP/LaTa2O7/GCE was demonstrated in real urine samples, achieving recoveries between 98.7 % and 103.5 %. The ion exchange provides a simpler method for the preparation of multifunctional electrochemical sensing.