Electrochemical multi-target detection of purine bases and uric acid using CoTMPyP/Ti4O92−/GCE sensor

A nanocomposite of 5,10,15,20-tetrakis (N-methylpyridinium-4-yl) porphyrin cobalt (III) (CoTMPyP) and titanium oxide (Ti 4 O 9 2− ) nanosheets was constructed using a stripping/self-assembly method for the first time. The morphology, structure, and composition of CoTMPyP/Ti 4 O 9 2− were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS), Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were utilized to analyze the electrochemical properties and detect uric acid (UA), guanine (G), and adenine (A). Under optimized conditions (0.1 M phosphate buffer, pH 4.0), the CoTMPyP/Ti 4 O 9 2− modified glassy carbon electrode (GCE) enabled simultaneous detection of UA, G, and A with detection limits of 396, 59, and 47 nM, respectively (S/N = 3). The linear detection ranges were 0.31–16.99 μM for UA, and 0.12–4.02 μM for both G and A. The stability and anti-interference ability of the CoTMPyP/Ti 4 O 9 2− /GCE sensor were also examined. Further tests in serum samples demonstrated recoveries of 98.1–109.7 % for the biomolecules, with relative standard deviations of 0.8–6.2 %. These results indicate excellent performance of the nanocomposite sensor for electrochemical detection.