LC-MS AND CZE OF DIANTHRONES FROM CASSIA-ANGUSTIFOLIA AND CASSIA-ACUTIFOLIA

Capillary zone electrophoresis (CZE) with multi-wavelength detection h as been used for the separation of the main dianthrones from Cassia an gustifolia. Optimum separation has been achieved with a fused silica c apillary and 0.1 M borate-sodium hydroxide buffer (pH 8.4). KCl and 5% of isopropanol has been added to the electrolyte. Applied voltage was 25 kV and capillary temperature constant at 20 degrees C. LC separati on of senna dianthrones was on reversed phase (RP 18) material with an acetonitrile-water solvent gradient containing 0.01% trifluoracetic a cid. UV detection was at 205 nm, column temperature 44 degrees C. LC-e lectrospray ionisation-MS was used for peak assignment and purity cont rol. New aloe-emodine dianthrone isomers could also be identified by t his technique. The established HPLC and CZE methods are suitable for q ualitative characterization and quantitative determination of sennosid es in crude senna extracts and phytopharmaceuticals.