236
ANALYTICAL CHEMISTRY
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sure differentials across the capillmy leak. A tyoical calibration curve appears in Figure 6.
Calibration of the instrument. may be ehnnged by m y of three variables: gas flaw rate, reagent flow rate, and electrical sensitivity. Each has it8 particular limitittions. The maximum gas flaw rate is dependent upon producing complete reaction of oxygen with the reagent in the reactor column; reagent flow rate is limited by desired response time; and electrical sensitivity is limited by signal to noise ratio. I n Figure 7 is shown a front view of the calibrating device. Gas and air connections are made a t the left side of the ealibrator. The controls for the pressure regulators are above the corresponding pressure gages. Figure 8 is a rear view of the calibrs, tor d h the door removed. The three glass chambers contain, from left to right, Drierite, regenerator, and scrubber solution.
difficulty through acceleration of the formation of rubbery deposits and through interferenoe with normal action of the polymerization catalysts. The main portion of the oxygen contamination was found to OCC.UP in the butadiene charged t o the prace~s and therefore the sample for the oxygen analyzer was taken from the butadiene charge line, Pressure of the butadiene sample was dropped from 100 t o 10 pounds per square inch gage by means of a vaporizer regulator. A trap was installed in the sample line to remove entrained liquids, mainly styrene, and the acidic gases and styrene vapor were removed by an Ascarite sorubber column. In the early operation of the analyzer in this installation, the reagent was found t o deteriorate after about 24 hours of eontinuous operation. This situation, first suspected of being due t o a Diels-Alder oondensrttion of the oxidized reagent and butadiene, was later traced to the presence of oarbon disulfide in the sample. The reaction of carbon disulfide with the sodium hydroxide of the rcagcnt solution results in the formation of sodium earhonnt,e and sodium thiocarbonate. Yellow thiocarbonate interferes with the photometric measurements and also reacts t o liherat,e hydrogen sulfide. A basic Carbitol (diethylene glycol monoethyl ether) scrubber was found t n iemove the carbon disulfide and results in an extension of tho useful life of the reagent of a t least 2 to 3 weeks. LITERATURE CITED
(1) Binder, K., and Weinland, R. F.. Ber. 46, 255 (1913). (2) Binder. K.. and Weinland, R. F.. Ges Whrld 59, 125 (1913). (3) Brady, L. J . . ANAL.CHEX.20, 1033 (1948). (4)Feiser, L. F., J . Am. Chem. Sac. 46, 2639 (1924). (5) nand, P. G. T.,J . Chem. Soc. 40, 1402 (1918). (6) Mohr. F., Z. anal. Che’hem. 12, 138 (1873). Analyst 34, 193 (1909). (7) R i d 4 S.,and Burgess, W. T.. (8) Sham. J . A,. IND.ENG.CHEY.,.ANAL. Eo. 14, 891 (1942). (9) White. H. A,, J . Chem. d l e l . .TIi8birw Soc. S. Af~ica 18, ?9Z (1918). (IO) Winkler, L. W.. Ber. 21, 2843 (1888). (11) Window. E. H., and Liebhafsky. H. :A,. IND. EN“.CHEK, ANAL.Eo. 18, 565 (1946).
Figure 8.
Exposed view of calibration device
R ~ c s i v r ofor review April 4. 1955. .Arabinose and >Fucose” [ANAL.CHEM.,27, 1998 (1955)l wlyxose should be added to the list of sugars mentioned in footnote ’.
L. M. WHITE In the subject index, page 204i, the 10th line under Sugars should read L-fucose instead of L-fructose.
