Supercritical fluid extraction of hydrocarbons and 2-alkylcyclobutanones for the detection of irradiated foodstuffs

Supercritical carbon dioxide can be used to carry out a selective and fast extraction (30 min) of volatile hydrocarbons and 2-alkylcyclobutanones contained in irradiated foods. After elimination of the traces of triglycerides still contained in the extracts on a silica column, the compounds were analysed by gas chromatography-mass spectroscopy (2-alkylcyclobutanones) and gas chromatography-flame ionization detection (volatile hydrocarbons). The present method was applied successfully to freeze-dried samples (1 g or less) of cheese, chicken, avocados and to various ingredients (chocolate, Liquid whole eggs) included in non-irradiated cookies. It was faster (4-5 h) than the reference methods EN 1784 (volatile hydrocarbons) and EN 1785 (2-alkylcyclobutanones), which take 1.5 days each. The minimal dose detectable by this method is, in addition, slightly lower than those of the reference methods. (C) 2000 Elsevier Science BN. All rights reserved.