Solid phase extraction—gas-chromatographic method to determine free cholesterol in animal fats

An analytical method to determine cholesterol in animal fats was developed. Cholesterol of four different animal fats was analysed by solid phase extraction, using porous silica derivatized with NH2 groups. The compound, purified from glycerides, was quantified as its trimethylsilyl derivative by gas chromatography coupled with a flame ionization detector. The results obtained with the proposed method were compared with those obtained with a saponification method. Proposed method repeatability and accuracy were reasonable. Coefficient of variation relative to standard deviation (s.d.) of repeatability was ⩽3.5%, while recovery was on average 96.2%. The limit of detection was about 0.8 μg of cholesterol per mg of sample loaded, with a s.d. of 0.01 μg. In conclusion, the proposed method is simple, fast and reproducible.