Simultaneous determination of the five alkaloids in Rhizoma Coptidis by nonaqueous capillary electrophoresis

A method for the simultaneous determination of berberine, palmatine, jatrorrhizine, magnoflorine and coptisine from Rhizoma Coptidis samples based on the nonaqueous capillary electrophoresis (NACE) mode has been developed. The effects of several important factors, such as nonaqueous solvents, running buffer system and its concentration and pH, separation voltage, temperature and detection wavelength, were investigated to acquire the optimum conditions. The optimum conditions for the separation were as follows: the selected running buffer was a methanol solution (pH 5.8) containing 40 mmol/L sodium acetate and 40 mnol/L ammonium acetat; the separation voltage was 25 k; detection wavelength was set at 254 n; the sample was injected at 5 kPa x 6 s and the column temperature was maintained at 20 degrees C. The analytes can be obtained good baseline resolutions in a 64 5 cm x 75 mu pm capillary (56 cm of effective length) within 20 min. The average recoveries of the established method were between 98 37% and 101 03%. The method is simple, accurate and reproducible, and can be used for the quality control analysis of Rhizoma Coptidis.