Sensitive and Rapid Resolution Liquid Chromatography-Time-of-Flight Mass Spectrometry for Qualitative and Quantitative Analysis of RadixAstragali and its Preparations

A new sensitive and powerful rapid resolution liquid chromatography-time-of-flight mass spectrometry (RRLC-TOF-MS) technique was developed to simultaneous qualitative and quantitative analysis of flavonoids and saponins in Radix Astragali and it's various preparations. The objective of the work was to explore the possibilities of combining the advantages of RRLC, in order to shortened analytical time, improve chromatographic resolution and increase peak capacity through rapid elution using a short column with 1.7 µm particles, with a high capture rate mass spectrometry combined with the accurate mass measurement of TOF-MS. RRLC system provides up to 5 times faster analysis and 60% higher resolution than conventional HPLC without sacrificing resolution, precision or sensitivity. By optimizing the fragmentor role, TOF-MS provides abundant fragment ions for structural confirmation. As a result, the identification and confirmation of multicomponents in Radix Astragali are provided by accurate mass measurements for each molecular ion and subsequent fragments, allowing unambiguous identification with similar or better performance as compared to tandem MS. Finally, RRLC-TOF-MS was used for the rapid and validated quality control of Radix Astragali through simultaneous determination of 13 major saponins and isoflavonoids. RRLC-TOF-MS can be a powerful tool for the analysis of multicomponent complex system of herbal medicines. Acknowledgements: Financial support for this research from the National Science Foundation of China (No. 90709020, 30530870) is gratefully acknowledged.