DEVELOPMENT OF GAS-CHROMATOGRAPHIC METHOD FOR DETERMINATION OF CHOLESTEROL OXIDES IN MEAT-PRODUCTS

A method of extraction, purification and gas chromatographic analysis of five cholesterol oxidation products (COPs) (7 beta-hydroxycholester ol, 5 alpha,6 alpha-epoxycholesterol, 25-hydroxycholestero1, 7-ketocho lesterol and cholestane-3 beta,5 alpha,6 beta-triol) has been develope d. The method is aimed at the determination of COPs in meat and meat p roducts, in particular dry sausages, where large differences in the co ntent of cholesterol and its oxidation derivatives may occur. Linearit y of response of trimethylsilyl ethers was defined. The minimum concen tration tested was 2.5 mu g g(-1) in the injected solution. The main f eature of the present work is the addition of a purification step of u nsaponifiables by SPE on silica cartridges. Extraction recoveries of C OP standard mixtures, performed with or without the SPE step, are eval uated. The introduction of the clean-up step results in high purity Sa mples without further losses in the entire process.