Continuous capillary electrophoresis with fl ow injection and its application for determination of Ephedrine and Pseudo-ephedrine in Chinese medicinal preparations.

摘要

This article presents a new, simple and rapid continuous separation method by combination of fl ow injection with capillary electrophoresis designed for the analysis of basic traditional Chinese medicines. The device was produced using commercial capillary and components readily available in analytical laboratory. In double-T con fi guration, the designed horizontal separation channel was 25 micro m i.d. x 146 mm length (an effective separation length of 93 mm) quartz capillary, with two vertical elicitation arms produced from 0.5 mm i.d. pump tubing. The capillary was embedded in a 40 x 20 x 3 mm organic glass base. Using the double-T con fi guration, continuous introduction of a series of samples was achieved. More than 3.00 resolution for ephedrine and pseudo-ephedrine were obtained using 100 mm borate buffer (pH 9.80) within 8 min in 25 micro m separation channel with an electrical fi eld strength of 137 V/cm (UV detection at 215 nm). The linear calibration range was 50-1500 micro g/mL (ephedrine, r = 0.9982; pseudo-ephedrine, r = 0.9990) for both analytes. The limits of detection were 2.65 micro g/mL for ephedrine and 2.92 micro g/mL for pseudo-ephedrine. In this device, the contents of ephedrine and pseudo-ephedrine in fi ve Chinese medicinal preparations were determined with RSDs (n = 5) in range 1.16-4.51% and recoveries in range 90.4-114.6%. Copyright 2004 John Wiley & Sons, Ltd.