New approach for application of high speed countercurrent chromatography coupled with direct injection of the powders of a raw material without any preparation, for isolation and separation of four alkaloids with high recoveries from Coptis chinensis Franch - Peng, J; Han, X; Xu, Y; Qi, Y; Xu, L; Xu, Q (J Liq Chromatogr Relat Technol, 2007)