To establish an UPLC-MS method for the simultaneous content determination of 4 saponins and 8 flavonoids, in order to analyze the effect of Astragali Radix directionally processed with organic acid on the content of glycosides and aglycones. The separation was carried out on ACQUITY UPLC HSS T_3(2.1 mm×100 mm, 1.8 μm), the mobile phase was eluted with the mixture of 0.1 mol·L~(-1) formic acid water solution and 0.1 mol·L~(-1) formic acid acetonitril in a gradient mode. The detection wavelength was 260 nm, the flow rate was 0.5 mL·min~(-1), the column temperature was 30 ℃, and the injection volume was 2 μL. Mass spectrometry analysis was performed with an electrospray ionization(ESI) source in a positive ion mode. The 12 constituents showed good linear relations within their own ranges(R~2≥0.999 2),with good average recoveries. The results showed no significant change in saponins but both qualitative and quantitative changes in flavonoids after directional processing of Astragali Radix with organic acid. The established method can provide methodological reference for analyzing the effect of Astragali Radix directionally processed with organic acid on glycosides and aglycones.
Keywords: Astragali Radix; UPLC-MS; content determination; directional processing; flavonoid; saponin.