A Large-Scale Soxhlet Extractor - Analytical Chemistry (ACS

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AhrALYTICAL EDITION

344

Vol. 3. No. 3

A Large-Scale Soxhlet Extractor’ S. Allan Lough DEPARTMENT OF C H E M I S T R Y ,

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UNIVERSITY OF N E V A D A , RENO, N E V .

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X ORDER to obtain large quantities of an oil for\ analysis, the extractor described herewith was devised. It

lends itself readily to adaptation to special problems and can be made from materials found in almost every laboratory. Near one end of the Pyrex glass tube A , of inside diameter 0.8 cm., a similar tube, B, was sealed in a t X a t the angle indicated by the dotted lines. This angle prevents excessive refluxing into the flask F. The second tube, €3, was then bent downward in a gentle curve until the lower portion of tube B was parallel to tube A . The jacket of a Liebig condenser, C, fitted with rubber stoppers, was placed on the upper portion of tube A . Another condenser jacket was cut off just below the water inlet and the edges were fire-smoothed. The other water inlet was sealed off in a flame. This served as thg extraction chamber. The siphon tube, E, was an ordinary copper tube of internal diameter 0.3 cm. A 2-liter Florence flask, F , was used as a chamber in which to boil the solvent and to collect the extract. The parts were assembled as indicated in the diagram and the whole was mounted, by the use of clamps, on a large ring stand. Corks coated with wet chrome-gelatin (1) were used to complete the joints a t H and K . Cork G was coated only on its under surface with chrome-gelatin. The chrome-gelatin was allowed to dry for 2 days. By virtue of the flexibility of the copper tube E, chamber D was removed from stopper G and the material to be extracted was introduced in a long, cloth sack. A ring, L, made of glass rod, was laid on stopper H . This ring supported the sack of material and prevented the occlusion of the outlet of the siphon. A glass tube, M , open a t both ends, was placed along the side of chamber D to make sure no air would be trapped within ring L, thus ensuring drainage of the chamber as soon as the liquid rose to the level P or only slightly higher. Siphoning is more complete if the siphon tube is longer and if extra bends are made in any convenient direction. The lower end of tube A should be a t least 1 cm. below cork G to keep solvent off the cork. If flask F is of large volume, chamber D can be filled many times with fresh material before the solution in F becomes too concentrated for longer boiling. If additional solvent is needed, it can be added a t the top of tube A. If only one charge of material is to be extracted, the siphon tube can be made of glass. 1

Received April 24, 1031.

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A Large-Scale Soxhlet Extractor

Literature Cited (1) Lassar-Cohn, “Organic Laboratory Methods,” translated by Oesper, p. 194, Williams & Wilkins, 1928.

Food Industries Welcome Legal Standards The food industries are shou ing a tendency to support legislation for standardization of all manufactured food products and for more extensive legal control of sanitary conditions in food manufacturing plants and establishments where foods are handled and sold, according to P. B. Dunbar, of the Federal Food and Drug Administration. Legislative control of advertising also has been endorsed by several organizations of national scope dealing in foods and drugs, and the industries in many instances are taking steps to control their advertising in the direction of myderation in the claims made. Quoting Doctor Dunbar: If I am correct in my estimate of the present attitude of the food industries toward the food law and of the value of the enforcement of the law to the industry, we may expect future developments to be in the direction of affording the consumer even greater guarantees of the integrity and good quality of food products. We may further expect the industry itself to take the steps necessary to bring about such extensions of the law.

“One of the most serious problems we have encountered is the determination of what actually constitutes a violation. The Food and Drugs Act is most general in its language. With one exception, that of butter, there is no legislative standard for food products. “After analysis, the general terms of the law must be applied to the commodity under consideration and a decision must be reached, first by the Department of Agriculture and later by the courts, as to whether the particular condition constitutes a violation of the law. Food products from a law enforcement standpoint very naturally divide themselves into three groups: first, those which are unmistakably legal; second, those just as definitely illegal. Between these two is a third group in a doubtful zone where the violation is not established so easily and yet where the most serious damage may be done to the consuming public and honest competitors unless abuses are definitely checked.”