A Reaction Tube for Determination of 17-I'etosteroids FREDERIC E. HOLMES Children's Hospital Research Foundation and the College of Medicine, University of Cincinnati, Cincinnati, Ohio
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N THE method of Holtorff and Koch ( 2 ) for the
and are transferred to the Evelyn colorimeter tubes as required. By the use of this reaction tube, long contact of strongly alkaline solutions with the colorimeter tubes is avoided. The small bottom part is of 15-mm. tubing (outside diameter) and has a depth below the ground joint of approximately 20 mm. The upper part is of 25-mm. tubing of any convenient length (an over-all length of 115 mm. was used). The stopper is easily made of 1mm. capillary tubing which gives it sufficient weight to sink in bichromate-sulfuric acid cleaning solution. The stopper is ground in u-ith a simultaneously lateral and rotary motion of the handle to produce spherical ground surfaces which fit in any position of the handle. In ,this laboratory, the potassium hydroxide solution is stored in and delivered from a small mercuryhealed buret (I, Figure 3) having a delivery tip sufficiently long to renrh to the top of the spiral glass rod. The tip of the Koch buret (.?) is also long enough for this purpose. M:iuy ordinary burets require an extension of the tip, preferably fused on.
determination of 17-ketosteroidsJ the p-I esence of more than a t,race of carbonate in t h e reaction mixture results in turbidity in the final diluted alcoholic solution. hbsorption of carbon dioxide during the reaction may be prevented by use of the tube shown in the accompanying figure, in which t h e concentrated alkaline solution is protected from contact with the air in the small space at the bott'om of the tithe helow the long-handled stopper. To avoid wetting the ground joint between the stopper and the shoulder of the tube, with resulting exposure of part of the solution, the 0.2-ml. portions of alcoholic extract, m-dinitrobenzene, and aqueous potassium hydroxide are delivered onto the top of a short glass rod fused into the bottom of the tube. The spiral form of t,hii rod aids in rapid thorough mixing with the diluent later. When sufficient time has elapsed for completion of the reaction, 10 ml. of alcohol are pipetted into the tube above the stopper. From a series of tubes the stoppers may be removed in rapid succession, thus decreasing the interval between dilutions to more nearly that re uired in mnking the readings. The concentrated saution and the diluent, alcohol are mixed by a rapid swirling motion,
Literature Cited 1 ) €Iolnies. 1;.
E., ISD. E S G .CHEM.,A N ~ LL'D.. . 12, 425
Sample Carrier for Organic Liquids FRANK 0 . GREEK1 Greenville College, Greenville, Ill.
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N THE ultimate analysis of organic liquids t h e common
sample carriers are sealed bulblets or open porcelain boats, t h e sealed bulblets for use with low-boiling liquids and t h e open boats for use with high-boiling liquids. A carrier device suggested for use with liquids of intermediate boiling temperatures does away a t once with t h e time consumed when sealed bulblets are used and t h e loss by evaporation when open boats are used. Figure 1 shows t h e device suggested. Using a piece of Pyrex tubing approximately 6 X 30 mm., the container is prepared as follows: One end is melted completely, blown slightly, and pressed firmly onto a flat, noncombustible surface. The stem is given a curvature and the open end is constricted by rotating in a flame until the opening is approximately 1 mm. in diameter. The container is filled by means of an eye dropper with a capillary tube, and may be used over and over again. The flat bottom makes it possible to stand the object directly upon the balance pan. For the actual combustion, the container is put into a, porepisin boat with the opening downward and toward the end of the boat hearer the catalyst (Figure 1, right). The curre in the neck keeps the liquid in the container until it is distilled out. Smd1 pieces of glass in the container aid in the regulnr distillntion of the sample into the boat. The speeds of distillation and combnctioii are thus controlled. 1
Present address, Bauer and Black, 2600 South Dearborn S t , Chicago, Ill.
J u s t a s some liquids do not volatilize completely when distilled from a bulblet carrier, so some liquids will leave a small carbonaceous deposit when distilled from t h e suggested
FIGURE 1 carrier. This difficulty may be partly overcome by decreasing the speed of distillation. However, if a small deposit does occur, it may be completely removed b y heating t h e carrier t o a dull red temperature for a few minutes while the oxygen flow is continued. Nevertheless this device will undoubtedly be limited, for practical use, t o liquids which char very little or not a t all when distilled. T h e author has obtained very satisfactory results with liquids of intermediate boiling temperatures. AIDEDb y a grant from t h e Illinois Academy of Science, and certain hpparatus loaned by Dr. Lauder of the Pet Milk Laboratory
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