Narrowbore high performance liquid chromatography of berberine and palmatine in crude drugs and pharmaceuticals with ion-pair extraction using cobaltthiocyanate reagent

For the simultaneous determination of berberine and palmatine from Phellode ndri Cortex, Coptidis Rhizoma and pharmaceuticals, a new narrowbore HPLC me thod was developed with a simple and selective sample clean-up using cobalt thiocyanate reagent. Samples were sonicated with 2% hydrochloric acid for 30 min and protoberberine-type alkaloids in the resulting mixture were extr acted with cobalt thiocyanate reagent and dichloroethane. The aliquot of di chloroethane layer was evaporated and the residue was dissolved for HPLC an alysis. The recoveries of berberine and palmatine from Phellodendri Cortex, and Coptidis Rhizoma were better than 90%. Calibration curves for berberin e and palmatine were linear over the concentration range of 0.1-50 mu g/ml. Limits of quantitation for berberine and palmatine were 0.5 ng. This sampl e preparation process can be used for the identification of protoberberine- type alkaloids from crude drugs and oriental pharmaceutical preparations. ( C) 1999 Elsevier Science B.V. All rights reserved.