Analysis of alkaloids in Coptis chinensis Franch by high performance capillary electrophoresis-electrospray ionization time of flight mass Spectrometry

Abstract

A new method for the analysis of alkaloids in Coptis chinensis Franch was established by high performance capillary electrophoresis-electrospray ionization time of flight mass spectrometry (HPCE-ESI-TOF/MS). The real samples were separated by an uncoated capillary. 50 mmol/L ammonium acetate containing 0.5% methanol (pH=7.2) was used as the running buffer, and separation voltage was 25 kV. A coaxial sheath flow interface was used as the CE-MS interface, and a 50% methanol-49.5% water- 0.5% acetic acid mixture was used as the sheath liquid with a flow rate of 4 mu L/min. The lens voltages in a positive ion mode with a collision induced dissociation (CID) voltage of 100 V were used for ESI-TOF/MS analysis. Seven alkaloids in Coptis chinensis Franch methanol extracts were separated and identified by CE-DAD and CE-ESI-TOF/MS. The coupling of HPCE separation with accurate mass measurement capability of ESI-TOF/MS provides an attractive tool for the identification of alkaloid compounds in Coptis chinensis Franch.