COMPARISON OF 3 METHODS FOR THE DETERMINATION OF OXYSTEROLS IN SPRAY-DRIED EGG

Three methods for the GC determination of oxysterols (OSs) in spray-dried egg, which combine different steps of purification, are compared. In addition, the efficiency of silica cartridges in the purification of OSs using four different systems of elution with increasing polarities is studied. The absence of cholesterol oxidation during the application of the analytical procedures is checked, and the linearity of the response and the chromatographic limits of detection and quantification are established. The methods are characterized by the calculation of precision and recovery for the different OSs. The method based on saponification alone is rejected, since it shows much lower precision. The method that includes saponification and silica cartridge purification offers higher reliability than the method based on cartridge purification alone? because it shows a higher precision and larger samples can be processed, which improves the limits of detection and quantification.