Simultaneous determination of purine bases, ribonucleosides and ribonucleotides was achieved by coupling capillary electrophoresis (CE) with wall-jet amperometric detection. A 200um diameter copper disk electrode was applied at working potential, +0.65 V vs. saturated calomel electrode. The current response of high sensitivity and stability was obtained in strong basic solutions which were suitable for satisfactory CE separations. The calibration curve was linear over 2-3 orders of magnitude and the limits of detection for adenine, guanine, xanthine, uric acid, adenosine, guanosine, adenosine-5-monophosphate and guanosine-5'-monophosphate were below 9 fmol (S/n=3). The use of this method for the separation and detection of compounds present in human plasma samples was reported.