635
V O L U M E 21, NO. 5, M A Y 1 9 4 9 LITERATURE CITED
(1) Blacet. F. E.,and Leighton. P. A.. IND.ENQ.CEEM., ANAT..E% 3,266(1931). (2) Christiansen, J. A,, J . Am. Chern. Soc., 47,109 (1925). (3) Krogh, A,. Skand. Arch. Phu.?ioZ., 20,279 (1908). (4) Soholernder, P. F.. J , Biol. Chhem., 167,235 (1947).
(5) Sewers, M. H.. and Storrnont, It. T., IND.END.CHEX..ANAL. Eo..9.39(1937). (6) sutton, T,c,,J , ,q& ~ ~ t15, 133 ~ (1938). ~ ~ ~ ~ (7) Swea~ingen.J. 5.. Gerbes. O., snd Ellis. E. W.. IND.EN^. CEEM.. ANAL.Eo.. 5.369 (1933). R~cslveo January 30,1948.
Simplified Blacet-Leighton Apparatus for Gas Microanalysis VICTOR M. LEWIS, University of Massachusetts, Arnherst Mass.
HE capillary buret type of gas microanalysis apparatus has Tfound extensive use in many branches of chemistry. I n its initial form, i t was described by Blacet and Leighton ( 1 ) and the technique of its use in the analysis of volumes as low as 20 cu. mm. of various gaseous mixtures has been fully described (Z-5). This piece of equipment, however, is relatively complicated, expensive to purchase, and difficult to make in the laboratory. It is also relatively tedious to operate, and the mioroburet is hard t o clean. Difficulty is also frequently experienced in getting the last small bubble of gas into the mioroburet from the analysis chamber. Swearingen et al. (6)described a horizontal modification of this apparatus which eliminated the trouble resulting from the necessity for equalizing the mercury level in the reservoir with that at the aero mark in the microburet. It also exerted less pressure on the mercury-actuating mechanism, with consequent more positive control of the mercury thread and less trouble with mercury leaks. The rubber mercury actuator described in the paper, however, has been found unsatisfactory in operation. The apparatus described here, and used with excellent results combines features described in various publications and e m he readily constructed from standard equipment.
stahdard tauer metal ioint N.;
Figure 2. Details of Gas Analysis Chamber
14/35. The pas microburet con-
ntt&hmknt to the mercury valve, and' the-opposite end of the mioroburet is fused to the gas analysis chamber (Flgure 2), whlch is a piece of glass tubing approximately 6 mm. in internal bare. The capillary tube has a right-angle bend in it, so that the andysis chamber dips into the mercury reservoir. It is iacketed by part of a 50-ml. buret, the graduations on whch serve for making readings in the microburet. The guide far the absorbent holder consists of a piece of brass rod through which is drilled a hole large enough to take the glass rod. The guide is attached to an upright support by means of a clamp holder. Additional gas reservoirs of the typo desoribed by Blaoet and Leighton (1)may be attached t o the side of the mercury reservoir by means of spring clips. The complete apparatus 1s shown m Figure 3. In operation, the gas sample is intreduced.into the analysis chamber and its volume is measured by drawlug i t up into the horizontal part of the microburet. Absorpbion takes place when
Figure 3. cue BV?S",U~"II
Assembly of Gas Microanalysis Apparatus
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tion the volume is again measured. Thus all operations are performed without transferring the sample; this results in both a saving of time and an increase in accuracy. If the microburet is attached to the valve by means of agroundglass joint, it may be readily removed for cleaning, or interehangeable burets of different capillmy bores may he used. LITERATURE CITED
(1) Blaoet. F. E..and Leighton, P. A., IND. ENG.CHEM.,ANAL.Eo: 3,266-9 (1931). (2) Blscet, F. E., and MacDonald. G. D., Ibid., 6,334-6 (1934). ( 3 ) Blsoet, P. E., MsoDonald, G. D., and Leighton, P. A,,Ihid., 5. 2724 (1933). (4) Blacet, P. E.,Sellers, A. L., and Blaedel, W. J.. Ibid., 12. 356-7 (1940). (5) Blaoet, F. E., and Volrnan. D. H., Zbid., 9,44-5 (1937). (6) Swearingen. J. S., Gerbes, D.. and Ellis, E. W., Ib& 5, 369-70 (1933).
Figure 1. Valve for Actuating Mercury Thread
R ~ o m v ~November n 10, 1947. t u r d Experiment Station.
Contribution 642, MQSsachmsettaAniaioul-
t
