Determination of sterols and their esters in fats by way of transesterification in different solvents

The interference of triglycerides in the analysis of sterols and their este rs in fats can be eliminated by transesterification of the sample dissolved in n-hexane with a solution of sodium hydroxide 2 mol/L, Since the analyte s are distributed equally in n-hexane and in methanol, better results can b e obtained by accurate measurements of the volumes, and processing the stan dards as the samples. Triglycerides and steryl esters are transesterified q uantitatively by a solution of sodium hydroxide 2 mol/L using diethyl ether as solvent. At 40 degrees C, ten minutes are sufficient to complete the re action. The sterols are determined in fats using a mass spectrometer detect or, at concentrations as low as 5 mg/Kg. Using FID, it was possible to anal yze sterols present in concentrations higher than 100 mg/Kg.