Development of an analytical method for twelve dioscorea saponins using liquid chromatography coupled to Q-Exactive...

A rapid method using liquid chromatography coupled to Q-Exactive high resolution mass spectrometry was developed for determination of twelve dioscorea saponins in Polygonti Rhizome. The separation was performed on a Alorich Ascentis C8 column (100 mm × 4.6 mm, 3 µm) with gradient elution of water and acetonitrile. All calibration curves showed good linear regression (r² >0.9947) within the linear range. The limits of detection and quantitation were in the range of 0.3-1.0 ng/mL and 1.0-3.0 ng/mL, respectively. The intra- and inter-day precision (RSD) were below 8.85% (n = 6) and 9.15% (n = 6), respectively. The recovery for the target compounds was within the range of 80.34-108.05%. The fragmentation pathways of twelve saponins were summarized in both positive and negative modes. The saponins which contain the same substituent groups and the different skeletons showed the same precursor ions and the similar fragmentation patterns in positive mode. However, different types of saponins can be distinguished in negative mode by the characteristic ions. The proposed method was applied to analyze six batches of Polygonti Rhizome samples for target compounds. This work promoted the quality control method for raw material or preparations which contain dioscorea saponins.