Quantification of saponins in Dioscorea panthaica Prain et Burk rhizomes with monolithic column using rapid resolution liquid chromatography coupled with a triple quadruple electrospray tandem mass spectrometry

The identification and quantification of saponins in crude extracts are challenging because of their similar structures and weak ultraviolet absorption. In this study, a rapid resolution liquid chromatography coupled with triple quadruple electrospray tandem mass spectrometric method was established to identify and quantify steroid saponins in the rhizomes of Dioscorea panthaica Prain et Burk, a traditional Chinese medicine. Six steroid saponins were simultaneously determined and quantified within 9 min. All analytes were subjected to a RP-18e (50 mm × 2 mm) monolithic column using a gradient elution program with a final detection using electrospray ionization tandem mass spectrometry in the negative ionization mode. The rapid resolution liquid chromatography/tandem mass spectrometry method achieved a limit of detection ranging from 0.52 to 20.40 ng mL−1 and a limit of quantification ranging from 1.20 to 75.20 ng mL−1 for the six studied steroidal saponins. The intra-day and inter-day precision (RSD) were less than 5.34%, and the recovery (RSD) was 1.50–3.51%. The highly sensitive and rapid method is suitable for the quantification of steroidal saponins in D. panthaica rhizomes.