Characterization and identification of steroidal saponins from the seeds of Trigonella foenum-graecum by ultra high-performance liquid chromatography and hybrid time-of-flight mass spectrometry.

Ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadrupole time-of-flight mass spectrometry (Qtof MS(E)) was used to rapidly separate and identify steroidal saponins from the crude extract of the seeds of Trigonella foenum-graecum (TFG). By using the UHPLC/Qtof MS(E) data acquisition strategy, both intact precursor and fragment ion information were obtained from a single injection. Fragmentation rules for five major groups of saponins from TFG are summarized, and possible fragmentation pathways are proposed. Accurate mass measurements of molecular ions and fragment ions as well as retention times permitted the identification or tentative identification of a total of ninety-five saponins based on comparison with reference standards. This included twenty-two pairs of isomers. Thirty of these saponins were identified for the first time.