The temperature of both the injector port and the detector
was 325 °C, and a split ratio of 1:10 was applied. PS were identified by
comparing their retention times with those of the standards derivatized
by the same procedure as the samples. For quantification, phytosterol
calibration curves of brassicasterol (9.9–59.2 μg), campesterol
(98.6–550.2 μg), stigmasterol (9.5–99.8 μg) and β-sitosterol (700.6–
2398.8 μg) containing 200 μg of IS (epicoprostanol) were performed.
The linear determination coefficients (R2) obtained for the different
phytosterolswere>0.989.Quantification of phytostanols (campestanol
and sitostanol) was performed using the response factor (Rf=0.879)
calculated for stigmastanol standard (the only commercially available
phytostanol) versus epicoprostanol