HPLC Determination of Sitosterol in Vegetable Oil

HPLC was applied to the determination of sitosterol in vegetable oil. The extraction conditions of additional sitosterol in the mixed oil were optimized as follows: the extraction times of 4 times; the centrifugal speed of 2 000 r·min-1; the saponification temperature at 80 ℃ for 3.5 h. C18 reverse-phase chromatographic column was used as stationary phase and a mixture of methanol and water (98.5+1.5) was used as mobile phase. UV-detection was made at the wavelength of 210 nm. Linear relationship between values of peak area and mass concentration of sitosterol was kept in the range of 12.5-1 000 mg·L-1 with detection limit (3S/N) of 5 mg·L-1. Values of recovery found by standard addition method were in the range of 86.2%-98.7%, and values of RSD′s (n=6) in the range of 2.4%-3.9%.