A New Distillation Trap
A Microburet
8. S. RASK,E. KAPLAN,Department of Biochemistry, The Johns Hopkins University, Baltimore, Md., AND H. C. WATEmAN, U. S. Department of Agriculture, Washington, D. C.
G. W. STANDEN AND M. L. FULLER Research Division, The New Jersey Zinc Company, Palmerton, Pa.
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MONG the common laboratory manipulations none can
be more troublesome than distillations of foaming and bumping liquids, especially under reduced pressures which fluctuate. T o overcome these troubles, various and familar distillation flasks, bulbs, traps, and columns have been devised. Few of these have the d e s i r e d combination of durability, simplicity in design, efficiency of operation, and general utility, w h i c h h a v e been combined in a fairly satisfactory way in the distillation t r a p i l l u s t r a t e d , It is e a s i l y constructed and functions very satis-
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FIGURE1. DISTILLATION TRAP
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N THE practice of quantitative spectrographic analysis in this laboratory, i t is necessary to measure small volumes of many different solutions with precision and rapidity (1, 2). In the course of routine analytical work, from one to four 0.1-cc. portions of fifty or more different solutions are measured daily. The use of one of the usual forms of microburet or fractional cubic centimeter pipet would require a clean buret or pipet each time a different solution is to be measured. To overcome this difficulty a microburet was designed in which the calibrated portion could be used over and over again without cleaning.
DESCRIPTION OF MICROBURET Figures 1 and 2 are photographs of the microburet. Tube A is a capillary measuring pipet of 2 CC. capacity, graduated in tenths of a cubic centimeter, each marking encircling the tube and being separated from adjacent raduations by about 0.375 inch (0.94 cm.). The tip end, B , of the measuring pipet is attached with a rubber tube t o the S-sha ed glass tube, C. At D is attached the delivering tube, E, whicg is a glass tube of 7 mm. outside diameter and 6 inches (15 cm.) long, with its lower end drawn to a tip. The liquid to be measured is drawn into and delivered from this tube, a clean tube being used for each li uid. The tubes are readily removed by detaching them from the ru%ber tubing connector, D, and the bronze spring clip, F . Water (tinted with a few drops of red ink) is introduced into the righthand half of C and into the calibrated tube in approximate amount indicated by the levels at G and H. Level H i s controlled hy varying the position of the top of the air column above it.
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FIGURE2. VALVE
factorily even under a fluctuating house vacuum, in distillations of either foaming or bumping liquids filling the distilling flask into the neck. The valve illustrated by Figure 2, attached b y means of fusion or a short piece of rubber tubing to the drain tube of the large safety reservoir, prevents liquids in the distillation flask from ascending into the safety reservoir but allows liquids to drain out of the reservoir and back into the distillation flask. If desired, the lower bulb identified b y dimension 16 M. M. R. in Figure 1 may be omitted without impairing seriously the operation of the trap. The dimensions specified are those of a trap suitable for a 1- or 2-liter ring-neck flask, and should be increased b y 25 to 50 per cent for traps to be used on 3- t o 5-liter flasks and probably doubled for traps to be used on 10-liter or larger flasks. RECsrYED
April 11, 1934.
FIGURE1 FIGURE2 SUPERIODIZED SEAWATERcontaining more than 500 mg. of : " iodine in salt form per liter is reported to be obtained by use of a 1 is is done by varying the position of the roller, J, which is recently patented French process (French Patent 763,083). anged to pinch the rubber tube, K , against a backing plate Iodine-saturated air is continuously pumped into a sea water any point, maintaining an air-tight seal continuously. The reservoir stocked with certain marine animals and plants, and through this medium the iodine eventually finds its way into b l l e r is mounted on a carriage, L,actuated parallel to the rubber tube by a long vertically mounted screw, the latter being rotated solution in salt form. 299
