DETERMINATION OF XANTHINE BY VOLTAMMETRY WITH TRIBUTYL PHOSPHATE CHEMICALLY MODIFIED ELECTRODE

AIM: To study a quantitative method for determination of trace amounts of xanthine by voltammetry with a tributyl phosphate (TBP) modified glassy carbon electrode. METHODS: In a medium of NH₄OH-NH₄Cl buffer, a well defined anodic peak was observed at 0.50 V (vs.SCE). RESULTS: The chemically modified film preferentially accumulates the xanthine. The relationship between peak current and the concentration of xanthine was linear in the range of 2.63×10^-7～7.89×10^-4 mol.L-1. The detection limit has been estimated as 6.57×10^-8 mol.L^-1. CONCLUSION: This method has been shown to be suitable for the determination of xanthine in human serum, urine and potato samples with satisfactory results.