DETERMINATION OF EGG-YOLK CHOLESTEROL CONTENT BY ON-COLUMN CAPILLARY GAS-CHROMATOGRAPHY

A rapid and accurate method for cholesterol determination by on-column capillary gas chromatography was developed and evaluated with three different yolk preparations. The cholesterol content of fresh, frozen and dried egg yolk was determined by either direct saponification or by chloroform-methanol (2:1, v/v) extraction prior to saponification. 5-alpha-Cholestane was used as an internal standard. The effect of sample size, quantity of triglycerides (soybean oil) and efficiency of hexane extraction were evaluated. The simple procedure for sample preparation eliminates the need for lipid extraction prior to saponification and multiple hexane extractions after saponification. Excellent precision and linearity were achieved.