Abstract: A novel electrochemical sensor poly-2,2-bipyridyl(Pbpy)/1-phenyl-3-methyl-4-(2-furoyl)-5-pyrazolone(HPM-α-FP)/glassy carbon(GC) composite film modified electrode was prepared for the determination of xanthine(XN). Cyclic voltammetry and differential pulse voltammetry were used to characterize the electrochemical behavior and to study the reaction mechanism of XN on the electrode. Compared with the bare GCE and Pbpy/GCE, the Pbpy/HPM-α-FP/GCE showed an excellent electrocatalytical effect on the oxidation of XN with a significant increase of the peak current. The results indicated that a synergistic effect existed between Pbpy and HPM-α-FP on the electrode. Linear calibration curve was obtained within the concentration range 6×10-7 to 1×10-5 mol/L and 1×10-5 to 1×10-4 mol/L, respectively, in phosphate buffer solution(PBS) of pH=8.0 with a scan rate 100 mV/s. The detection limit was 1×10-8 mol/L. This electrode could be used for the direct detection of XN in the presence of uric acid(UA) and ascorbic acid(AA), and also the XN in urine samples with satisfactory results.

Key words: Poly-bipyridyl, Acylpyrazolone, Xanthine, modified electrode