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Compact Field Apparatus For Determination of Lewisite or Mustard Gas JOSEPH W. KOUTEN, J. 6. SHOHAN, AND W. FAITOUTE MUNN West Orange Gas Defense Laboratory, West Orange, N. J. for lewisite. A rubber stop er is very satisfactory here, as neither lewisite nor mustard gas any immediate effect upon it. After the test has been completed, the entire apparatus is taken apart and thoroughly scrubbed with calcium hypochlorite sludge. Inner tube 3, centrally located in the upper part of tube 1, is supported in a cork having a small V cut out along its entire length, so that when cork and tube are in position, the gas evolved will vent through this cork and revent the building up of pressure during the test. A slight b d or bulge is blown 1.25 cm. (0.5 inch) from the lower extremity of this inner tube. Tube 4, connected with the upper end of tube 3 by 10 cm. (4 inches) of rubber tubing, has a capacity of 15 cc. Tube 4 has 1.5 grams of flake sodium hydroxide placed in it and is then tightly stopIts contents will remain in perfect condition for any ength of time. A small glass bead fits into the rubber tube, connecting tube 4 with the up er end of tube 3, about 2.5 crn. above the point where the rugber tube is fastened to tube 3. This bead, or valve, prevents liquid from entering tube 1. When the test is to be made, the side of the bead is pinched with the thumb and forefinger, causing a channel to be formed through which the caustic solution flows into tube 3, then into tube 1. The filter paper disk upon which the color reactions are produced is cut to a diameter slightly smaller than that of the upper part of tube 1. In its center is cut a small hole of a size which will allow the disk to be pushed on the lower end of tube 3 up to the point where it meets the bulge. A small rubber band is twisted around the tube, flush with the underside of the paper disk, to keep it in position. The supporting stand may consist of nothing more than a square block of wood containing a slight hollow in the center to support the bottom of tube 1 and an upright piece of wood with a clip near the top to support the upper end of the tube. CONSTRUCTION OF VIAL A N D CAPILLARY TUBE. The vial is made from soft-glass tubing of about 1.25-cm. (0.5-inch) diameter, the lower end being drawn down to fit the 0.6-cm. (0.25-inch) hole in the rubber stopper and sealed. The total length of the vial is 7.5 cm. (3 inches). The capillary tube, which acts as a dropper tube, inside the vial is 3-mm. glass tubing, open a t the lower immersed end and having a very small hole blown in it just below the point where the lower end of the rubber stopper, which closes the vial, is located. The upper end of the capillary tube is sealed.
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EMBERS of the West Orange, N. J., Gas Officers’ Defense
Staff have developed a compact apparatus for field detection of lewisite or mustard gas (liquid). I t s simplicity makes it adaptable also for laboratory use. When liquid lewisite is treated with 15% sodium hydroxide solution, acetylene is liberated and is detected in this apparatus by the formation of deep red cuprous acetylide on a disk of filter paper, freshly moistened with cuprous chloride solution. If the cuprous chloride solution is practically colorless, the moistened disk turns pink, then gradually deep red if considerable acetylene is generated; if the cuprous chloride solution is blue, the disk turns purplish red and the color gradually deepens. The reaction is distinctive, sensitive, and quantitative. To test for liquid mustard, the paper disk is moistened with sodium platinic iodide-starch solution, without addition of sodium hydroxide or other re9,gent. In the presence of mustard the color changes from violzt to strong blue. Gentle heat hastens the reaction.
Pered.
APPARATUS
The main tube, 1, has an expanded bottom bulb 3.75 cm. (1.5 inches) in diameter, on the side of which is. blown a 2.5-cm. jlinch) opening. A rubber stop er, 2, fits tightly in this opening and is provided with a 0.6-cm. b.25-inch) hole in which is pushed tightly the end of a small vial containing the cuprous chloride reagent used to moisten the disk just prior to making the test
PROCEDURE
Place the contaminated material, such as sand, leaves, rubble, twigs, etc., in tube 1 through the 2.5-cm. opening by means of tweezers or tongs then firmly place rubber stopper 2 in this opening. Remove tube 3 with its dry paper disk, take out the capillary tube, and wet the disk with cuprous chloride solution by touching the open end of the capillary tube to the disk. Immediately re lace the capillary tube and cork in the vial and return the inner tu%, with its moistened paper disk to tube 1. Remove the stopper from tube 4 and pour in 10 cc. of water, leaving the stopper out. Hold tube 4 straight above tube 3 and pinch the bead inside the rubber tubing, regulating the flow of solution, so that all the sodium hydroxide flake will have dissolved by the time all the water has run into tube 3 and thence into tube 1. (Considerable heat will be evolved, owing to the dissolving of the caustic flake.) The reaction of the caustic solution upon the lewisite is practically instantaneous and if any such “gas” is contained in the sample being examined, the filter paper disk will soon show its presence by a change of color. Although the minimum sensitivity of this test when applied in the apparatus hm not been determined, the West Orange gas laboratory staff has obtained very positive results with less than 0.25 drop of lewisite. The presence of arsenic may be confirmed by extracting the contaminated material, after the treatment with sodium hydroxide, with a small amount of water, neutralizing the solution thus obtained with 50% sulfuric acid, and then testing for arsenic by the Gutzeit test, using mercuric bromide paper and not mercuric chloride paper for the arsine color reaction, 255
INDUSTRIAL AND ENGINEERING CHEMISTRY
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ADVANTAGES OF APPARATUS The chamber in which the acetylene or mustard vapors are brought into contact with the moistened reactor paper is very small, thus concentrating the amount of reactive gases in contact with the reagent. The use of dry sodium hydroxide flake in tube 4 prevents deterioration and spilling of alkali. The addition of the water to the dry sodium hydroxide just before use produces considerable heat, speeding the reaction. In the case of lewisite, this decreases the solubility of the acetylene in the liquid reactive mass and thereby increases to a maximum the amount of acetylene generated. The filter paper disk, of practically the same area as the
chamber through which the reactive vapors must pass, gives quicker and better contact with such vapors than a paper strip suspended within the reaction chamber. The disk is placed a t a point where contamination with the caustic solution is impossible. The rounded bottom of tube 1 is an advantage if one desires to heat the contaminated material gently (in case of mustard gas) for more rapid volatilization of the vapors. Placing the cuprous chloride solution in the small vial, which in turn is carried a t all times in the rubber stopper, eliminates the necessity of carrying a separate bottle for this reagent. The entire apparatus may conveniently be carried in a coat pocket or field kit.
Routine Determination of Zinc in Magnesium
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Vol. 16, No. 4
Alloys
Volumetric Method
LLOYD GEORGE MILLER, ALBERT J. BOYLEI,
AND
ROBERT 8. NEILL
Technical Service Laboratories, &sic Magnesium, Incorporated, Las Vegas, Nev.
A rapid accurate volumetric method for the determination of zinc in magnesium alloys involves the precipitation of zinc in 1 N hydrochloric acid with excess standard potassium ferrocyanide. The excess is subsequently determined b y titration with standard ceric solution. M ~cadmium, ~tin, and ~ smallamounC ~ of iron d o not interfere. The method is capable of an accuracy ranging from 1 to 5% of the amount of zinc present in magnesium-base alloys of high and low zinc content, respectively.
tion stand overnight, filter, and standardize against zinc chloride solution. CERICAMMOXIUM SULFATE, 0.025 N solution (6). Dissolve 22 prams of ceric ammonium sulfate dihydrate in 1 liter of distilled Gater containing 28 ml. of concentrated sulfuric acid. The sohtion is approximately N . Filter , the solution, and adjust ~the ~ so that~ 1 0.025 ml. of~solution is equivalent to 1 ml. of volume standard potassium ferrocyanide solution. TRI-0-PHENANTHROLINE FERROUS SULFATE[(CizHeNz.HzO)iFeS04] solution. Dissolve 1.485 grams of o-phenanthroline (C12HsN2.H20)in 100 ml. of 0.025 ,M aqueous solution of ferrous Sulfate. STANDARD ZINC SOLUTION,Dissolve 1 gram of zinc metal, c.P.,in 20 ml. of 1 to 1 hydrochloric acid. Dilute to 1 liter. Potassium ferricyanide, C.P., 0.5% SOhtiOn. Concentrated C.P. Dilute hydrochloric hydrochloric acid, lead, nfercuric chloride, saturated solution.acid, 1 to 10. Test ~
IN
~
'
VIEW of the large number of magnesium-base alloys containing zinc, the determination of this element has become increasingly important to the magnesium industry. The Lang method (4)modified by Casto and Boyle (1) requires the eliminaPROCEDURE tion of manganese, cadmium, tin, and copper from the sample, Weigh a 2.000-gram sample of the magnesium alloy into a 400and is limited largely to magnesium-base alloys containing alumiml. beaker, and add 75 ml. of distilled water and 25 ml. of conand manganese* If the zinc content of the magnesium alloy centrated hydrochloric acid. Cover the beaker with a watch is less than 1% a preliminary separation with hydrogen suiglass to avoid loss by mechanical spray. If copper is known to fide becomes necessary. The method described in this Table I. Estimation of Zinc in Standard Chloride Solutions paper is applicable to magnesium(In the presence of magnesium, manganese, aluminum, cadmium, tin, iron, and mercury) base alloys containing from 0.05 Milligrams of Metal Present" to several per cent zinc, and is Mercury ... ... ... . . . ... ... ... 500 recommended for routine Tin ... . .30 " 6 0 .,. ...... ... .... .. 100 Manganese ... 60 ... "30 30 30 ... analytical control. Cadmium, Cadmium . . . ... ... . . . 60 60 38 38 38 ... tin, and manganese offer little Aluminum ... ... 165 ... ... 165 165 165 ... Iron ... ... . . . 1 2 1 1 interference. The error due to Magnesium 2000 2000 2000 2000 2000 2bbo 2000 2000 2000 2000 iron is largely compensated by Zinc Taken Milligrams of Zinc Found a step in the procedure emMO . ploying the use of potassium 10 9.70 9.52 9.83 10.01 9.57 9.86b 9.65 9.83 10.37 9.57 10.70 10 9.55 9.88 10.01 10.42 9.52 10.75 9.70 9.60 10.83 10.09 10.29 ferricyanide. If copper is pres10 9.91 9.96 10.55 9.96 9.93 9.78 10.62 9.45 . . . . . .9.80 . . . . .9.98 . . . . 10.44 . . ent, it is removed with test lead. Av.error -0.28 -0.27 -0.06 +0.41 -0.29 $0.69 -0.04 +O.OS -0.38 +0.40 ... .
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I
I
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.
~~
20 20 20
REAGENTS
Av.error P O T A S S I UFERROCYANIDE, M 50 0.025 N solution. Dissolve 11.2 50 grams of potassium ferrocyanide 50 t r i h y d r a t e analytical reagent Av.error grade, in 1 liter of distilled 75 75 water containing 0.2 gram of 75 sodium carbonate. Let the soluAv.error address: College of Medicine, Wayne University, Detroit 26, 1 Present
Mich.
19.94 19.74 20.02 20.43 19.94 20.76 20.30 20.04 20.07 18.94 20.04 20.15 20.17 20.51 20.04 20.68 20.20 20.30 20.02 18.94 19.46 19.76 20.02 20.04 20.45 20.02 20.61 20.04 20.33 20.17 -0.09 - 0 . 0 3 +0.08 +0.46 tO.00 $0.68 +0.18 $0.22 SO.09 -0.65 50.00 49.64 50.25 50.43 49.38 50.76 50.23 50.18 50.12 49.92 49.82 49.69 50.48 50.66 49.72 50.66 49.56 49.74 49.74 50.18 49.84 49.79 50.15 50.76 49.59 50.59 50.12 49.82 50.07 50.18 -0.11 -0.29 +0.24 +0.61 -0.44 +0.67 -0.03 -0.09 -0.02 +0.13 75.37 75.29 75.44 76.26 74.75 76.39 75.55 74.60 74.14 75.01 74.83 75.26 75.37 75.80 75.32 75.75 75.44 75.24 74.93 75.26 75.03 74.29 75.60 75.90 74.65 75.96 75.75 74.65 74.83 75.14 +0.08 -0.03 +0.47 +0.69 -0.09 +1.03 +0.58 -0.19 -0.37 +0.13
All determinations made in hydrochloric acid solution. 6 Results in this column determined b y potentiometric titration.
a
19.76 19.87 49.87 49.48
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