Abstract:

An system of two-dimensional liquid chromatography (2D-LC) coupled with mass spectrometry was developed for the separation of components in Gegen Qinlian decoction, a complex traditional Chinese medicine. A CN column was used in the first dimensional chromatography, with gradient elution using water and methanol as the mobile phase A and mobile phase B, respectively; an ODS column was used in the second dimensional chromatography, with gradient elution using 20 mmol/L ammonium acetate buffer and acetonitrile as the mobile phase A and mobile phase B, respectively. The effluent was detected by mass spectrometry with electrospray ionization （ESI）/atmospheric pressure ionization （APCI） combined ion source and positive and negative scan modes. The components in Gegen Qinlian decoction was separated with the 2D-LC system with peak capacity up to 8000. Compared with UV detection, MS detected more components, especially in the negative mode. The 2D-LC/MS system provides higher peak capacity, better resolution and the capacity of peak identification. It is suitable for the analysis of complex samples such as the traditional Chinese medicine.

Key words: active compounds, electrospray ionization/atmosphere pressure ionization （ESI/APCI） combined ion source, Gegen Qinlian decoction
, two-dimensional liquid chromatography-mass spectrometry