Abstract: This paper reports the separation and determination of caffeine,9-N-dihydroxypropyltheophylline, theobromine, adenine, guanine,theophylline, xanthine, uric acid and 6-mercaptopurine by capillary zone electrophoresis, In an uncoated fused silica capillary(70cm ×75μm i.d., effective length 63 cm), the above mentioned materials can be separated within 7 min in the optimum conditions;0.01 mol/LpH=10 borate buffer,30℃,25 kV,260 nm and 1s load.Efficiency to 3.0×10⁵ the number of theoretical plate is achieved.The detection limit is fmol.The results of urine sample analysis are satisfactory.

Key words: Capillary zone electrophoresis, Purine bases, Urine sample