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

Three methods for the GC determination of oxysterols (OSs) in spray-dr ied egg, which combine different steps of purification, are compared. In addition, the efficiency of silica cartridges in the purification o f OSs using four different systems of elution with increasing polariti es is studied. The absence of cholesterol oxidation during the applica tion of the analytical procedures is checked, and the linearity of the response and the chromatographic limits of detection and quantificati on are established. The methods are characterized by the calculation o f precision and recovery for the different OSs. The method based on sa ponification alone is rejected, since it shows much lower precision. T he method that includes saponification and silica cartridge purificati on offers higher reliability than the method based on cartridge purifi cation alone? because it shows a higher precision and larger samples c an be processed, which improves the limits of detection and quantifica tion.