|The determination of minor components,
such as sterols and tocopherols in oil
is usually carried out
by gas chromatography
after prior treatment. This includes the concentration of the components,
separation of the interfering matrix components and derivatization
of the analyte
prior to the actual measurement.
The current technology is based on a fractionation by HPLC, derivatization of sterols (to silyl derivatives) with subsequent determination by gas chromatography. A direct determination of sterols by HPLC (after enrichment and separation of interfering matrix components) can be performed only by a light scattering detector.
However, the sterols can be determined by fluorescence detection after derivatization with HPLC very easy. This results in the ability to detect all analytes by means of highly sensitive fluorescence detection even from the native oil. For the separation of the sterols, both NP and RP columns can be used for derivatization.
This application allows the determination of all target components by RP-chromatography, so that eliminates the difficult handling with normal phase and a much higher stability of the results is achieved.