Determination of barbituric acid and 2-thiobarbituric acid with end-columnelectrochemical detection by capillary electrophoresis

Capillary electrophoresis (CE) with end-column electrochemical detection (E C) of barbituric acid (BA) and 2-thiobarbituric acid (TA) has been describe d. Under optimum condition, BA and TA were separated satisfactorily, and a response of high sensitivity and stability was obtained at a detection pote ntial of 1.25 V versus Ag/AgCl. Optimized end-column detection provides det ection limit as low as 0.5 and 0.1 mu M for BA and TA, respectively. The ca libration graph was linear over three orders of magnitude. The relative sta ndard deviations (n = 10) of peak currents and migration times obtained for both BA and TA were 3.4, 3.7, and 1.7, 1.2%, respectively. The proposed me thod has been applied to analyze water sample with satisfactory results. (C ) 2000 Elsevier Science B.V. All rights reserved.