Abstract
Total fat and water content of mouse livers and carcasses had to be determined for studies to be reported elsewhere. Previous work of this type(1) required drying of the tissue or carcass to constant weight to determine the water content before Soxhlet extraction of the fat could be undertaken. The method to be described eliminates the time required for this drying process. Distillation of body water and extraction of fat were performed in one simple operation based on the lower specific gravity (0.87) and higher boiling point (110.6°C) of toluene as compared with water and the solubility of lipids in toluene.
The apparatus shown in Fig. 1, consists of a 300 ml or larger short neck round bottom flask (AHT 5341)† to which a Soxhlet extractor (AHT 4987-C)‡ is fitted. A piece of stainless steel wire cloth, 20 mesh, is cut to fit snugly into the extractor just above the syphon opening. Pyrex glass wool is placed on this screen to the level of the syphon bulb. If properly packed, glass wool will retain even uncoagulated blood and prevent it from entering the flask.
A 25 ml graduated Stark-Dean distilling receiver with a return tube (AHT 7618-P2) is attached to the Soxhlet extractor by means of a straight adapter. A 300 mm Allihn condenser (AHT 3908-A) is joined to the distilling receiver and connected to the water supply. A drying tube, containing Tel-Tale Silica Gel, is attached to the top of the condenser by a short piece of plastic tubing. Heat is supplied by an electric flask heater (AHT 6134-N) and a 6 feet × 1/2 inch flexible heating tape (AHT 6148-A) which is wrapped around the extractor and connecting arm of the distilling receiver.
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