Determination and purification of sesamin and sesamolin in sesame seed oil unsaponified matter using reversed-phase liquid chromatography coupled with photodiode array and tandem mass spectrometry and high-speed countercurrent chromatography

In Asian countries, sesame seed oil unsaponified matter is used as a natural food additive due to its associated antioxidant effects. We determined and purified the primary lignans sesamin and sesamolin in sesame seed oil unsaponified matter using reversed-phase liquid chromatography coupled with photodiode array and tandem mass spectrometry and high-speed countercurrent chromatography. Calibration curves showed good correlation coefficients (r(2) > 0.999, range 0.08 and/or 0.15 to 5 mu g/mL) with a limit of detection (at 290 nm) of 0.02 mu g/mL for sesamin and 0.04 mu g/mL for sesamolin. Sesame seed oil unsaponified matter contained 2.82% sesamin and 2.54% sesamolin, respectively. Direct qualitative analysis of sesamin and sesamolin was achieved using quadrupole mass spectrometry with positive-mode electrospray ionization. Pure (> 99%) sesamin and sesamolin standards were obtained using high-speed countercurrent chromatographic purification (hexane/ethyl acetate/methanol/water; 7: 3: 7: 3). An effective method for determining and purifying sesamin and sesamolin from sesame seed oil unsaponified matter was developed by combining these separation techniques for standardized food additives.