Liquid chromatographic separation of the alkaloids in coptis-evodia herb couple

摘要

A total of seven quaternary and ten tertiary alkaloids in the coptis-evodia herb couple were separated on a Cosmosil 5C_(18)-MS column (5 mu m, 250 X 4.6 mm I.D.) using a mixture of methanol and sodium dodecyl sulfate-NaOAc-HOAc buffer or NaOAc-HOAc buffer as eluent. wherein the latter was found to be better for the analysis of coptis-evodia crude extract. Experiments showed that retention times of the quaternary alkaloids were mainly governed by the composition of buffer used and those of the tertiary alkaloids were chiefly determined by the content of organic modifier in the mobile phase. Linearity of around two orders in the magnitude of concentration was generally obtained and limits of detection for these compounds were in the range of 0.28-6.77 ng. The relative standard deviations of retention times were less than 1% (n = 6). Contents of the coptis-evodia herb couple or Chinese herbal preparation containing this herb couple could easily be determined by the proposed method.