PTA/CeO2@Pt-based electrochemical sensors to detect xanthine and uric acid, and evaluate fish freshness

Abstract

In the present study, we constructed an electrochemical sensor using three materials, namely, cerium dioxide (CeO2) composite platinum (Pt) and polymer 3-amino-5-mercapto-1,2,4-triazole (PTA), prepared by hydrothermal method, to detect xanthines and uric acid. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier infrared spectroscopy (FT-IR) were used to characterize the morphology, elemental composition, and structure of materials. The results demonstrated that the PTA/CeO2@Pt composites were prepared. The electrochemical behavior of xanthines and uric acid on PTA/CeO2@Pt composite electrodes was assessed by cyclic voltammetry (CV) and differential pulsed voltammetry (DPV). The results demonstrated that the dropping amount was 20 µL under a phosphoric acid buffer solution (pH 6). The peak current of xanthine (XA) demonstrated two good linear relationships with concentration, the linear regression equation was IXA = 0.3265CXA + 8.1967 R2 = 0.994 in the concentration range of 10–138 µmol/L, whereas it was IXA = 3.9884CXA + 51.661 R2 = 0.992 in the concentration range of 139–330 µmol/L. The detection limit was 10.36 × 10–7 M. The freshness of fish meat was evaluated, and the correlation analysis between evaluation results and results of xanthine detection in fish meat by PTA/CeO2@Pt electrochemical sensor demonstrated that r = 0.945 and P < 0.01 had a good correlation. The sensor could be used to determine the xanthine content in fish to reflect the freshness of fish, thus displaying good application prospects.