畜牧学方面 英译汉2

KeywordsCarbondioxide.SupercriticalfluidExtraction.Capillarygaschromatography.Freecholesterol.Egg-containingfood.Solid-phaseextractionIntroductionTheuseofsupercriticalflu... Keywords Carbon dioxide . Supercritical fluid Extraction . Capillary gas chromatography . Free cholesterol . Egg-containing food . Solid-phase extraction Introduction The use of supercritical fluid extraction (SFE) for sample preparation on an analytical scale has become more popular because it allows a lower solvent consumption， a reduction in the time of sample treatment and little sample manipulation. This leads to purer extracts and a reduced possibility of artefact formation. Several methods have been proposed for the determination of pollutants (pesticides， PAHs， PCBs)， pharmaceutical drugs and fragrances [1] with supercritical carbon dioxide (SC-CO2). The analytical extraction of cholesterol by SFE for the quality control of food has been carried out on dried egg yolk [2， 3]. More recently cholesterol was extracted by SFE from bakery products， milk [4] and chicken liver [5]; quantitation was performed by an enzymic method or high-performance liquid chromatography (HPLC)， respectively. A rapid sample preparation for the determination of free cholesterol in eggcontaining food is reported here. To achieve this， SCCO2 extraction was coupled on-line with solid-phase extraction (on-line SFE-SPE)， thus obtaining extraction and automatic clean-up of cholesterol in one step prior to gas chromatographic analysis.