A simplified method for the quantification of total cholesterol in lipids using gas chromatography

Abstract

In this study, a quick and simple protocol for determination of total cholesterol in fats and oils using gas chromatography was established. Practically, about 0.1 g of lipid was saponified with 0.5 n NaOH in methanol, followed by methylation in a 10% boron trifluoride methanol solution (BF 3/MeOH). The methylated sample was then extracted with 2 ml ether, added with 100 μl 0.4% (w/v) 5α-cholestane as internal standard, and analyzed by gas chromatography. The whole procedure for the quantification of cholesterol in lipids by the above method would take only about 30 min. Standard addition test revealed that the recovery of cholesterol ranged from 94 to 107% with a coefficient variance not more than 7.1%. Comparisons of cholesterol content in 12 different fats and oils pre-treated with AOAC saponification and BF 3 methylation followed by GC analysis also showed no significant difference. These results suggested that, without losing accuracy, BF 3 methylation method for total cholesterol quantification not only consumes less solvent but also reduces by more than half the time required for the AOAC method.