Determination of multiple active constituents in Da-Huang-Xiao-Shi decoction using HPLC-LTQ-Orbitrap mass spectrometry: Application in comparing the differences in the formula and its constituent herbs.

Da-Huang-Xiao-Shi decoction (DHXSD) is a traditional Chinese medicine formula and is used to treat cholestasis. In this study, we developed a reliable and comprehensive HPLC coupled with a linear ion trap-Orbitrap mass spectrometry method for the separation and determination of 21 components including six alkaloids, five anthraquinones, three tannins, three terpenes, two iridoid glycosides, one organic acid and one flavonoid in DHXSD. A C18 column was eluted using a gradient mobile phase at a flow rate of 1 ml/min. Detection was operated with an electrospray ionization source in positive and negative ion modes using selective ion monitoring. The calibration curves for all analytes showed good linearity (r > 0.9901), and the inter- and intra-day precision did not exceed 4.98%. The recovery, repeatability and stability were also within the acceptable limits. The method was successfully applied to determine multiple active constituents in DHXSD and its constituent herbs. Compared with Da Huang, the total contents of the five anthraquinones were significantly higher in DHXSD. However, the changes in the components from Zhi Zi/Huang Bo were complicated in DHXSD. The study could serve as a fundamental reference for establishing comprehensive DHXSD quality control measures and be helpful to understand some compatibility laws of DHXSD.