Rapid quantification and characterization of soyasaponins by high-performance liquid chromatography coupled with electrospray mass spectrometry.

A method using high-performance liquid chromatography (HPLC) with electrospray ionization mass spectrometry (ESI-MS) in the negative mode is presented for the quantification and characterization of different soyasaponins using six authentic soyasaponin standards. This method was successfully applied to the rapid separation of diverse soyasaponins, more than 50, including soyasaponins A in different degrees of acetylation, and soyasaponins B in both their 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated and non-conjugated forms in different samples in one single run for only 30 min. Standard calibration curve was linear over the concentration range of 0.010-1.0 mg/L for each soyasaponin. Within-day and day-to-day relative standard deviations were less than 9.2 and 13.1%, respectively.