Rapid and reliable method for analysis of raw and honey-processed astragalus by UPLC/ESI-Q-TOF-MS using HSS T3 columns

A novel method has been developed for rapid analysis of the major constituents in Radix Astragali and honey-processed Astragalus within 23 minutes using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS). Separation analysis was performed on HSS T3 columns with a gradient elution of acetonitrile-water containing 0.1% formic acid at a flow rate of 0.3 mL min(-1). Methodology validation showed that the established method had good repeatability (RSD < 8.07%), intra-day precisions (RSD < 4.20%), and stability (RSD < 7.78%). Accurate molecular weight and characteristic fragment ions obtained from Q-TOF-MS provided a reliable criterion for the structural characterization of the major compounds in raw and honey-processed Astragalus. 35 major constituents, including flavonoids, isoflavan, pterocarpan, and saponins, were identified or tentatively characterized by comparing their retention times and MS spectra with those of authentic standards and literature data. Furthermore, quantitative analysis revealed that the content changes of chemical compositions could cause the tonic effect differences between raw and honey-processed Astragalus. The established method is rapid and reliable for simultaneous analysis of constituents in an extract of Radix Astragali. Moreover, this method will simplify further studies of metabolism and pharmacodynamics and will encourage the use of HSS T3 columns in similar traditional Chinese medicine research.