Document vVRg4KdJ2zkvox26d0dZop5Q9

mm ifeg- 184 FRANK A. PATTY SAMPLING AND ANALYSIS OP CONTAMINANTS 185 Sulfur dioxide and hydrogen sulfide each require only the usual solution of iodine in potassium iodide, and the reactions are the common oxidation ones: II. Methods Requiring Laboratory Analysis MJ(..-,''''^a;AL0GENATBD HYDROCARBONS COMBUSTION APPARATUS 60a "1" 2 HaO *f I* ^ HsSO* 2 HI HsS "I" la --^ 2 HI S A similar result is achieved by utilizing the color developed by the solutiomof ^Se^a_jTa|ddee:vices have been proposed for the combustion of halogenated hydro\feors in the atmosphere. Passing the atmosphere through a heated tube ' i|iplatinum foil was first utilized by Pregl24 and several modifications the contaminant in the sampling medium. This simple type may be utilized I estimating ammonium picrate. Ammonium picrate in water, with no added ref agents, produces sufficient color that 0.01 mg. in 10 ml. of water is readily d|| tinguishable from none and from 0.02 mg. Each sample is collected until a visiblg color is obtained and then that color is compared with standards, in the fieral (Ammonium picrate, TNT, Tetryl, and other contaminants in their class naye| been successfully collected by means of the midget impinger regardless of whetflef they occurred as vapor or particulate matter.) TNT and Tetryl samples may^jL collected and semiquantitative results may be obtained in the field by the use*|fp diethylaminoethanol20 in the impinger; but, because color develops gradually ana continuously over many hours, really satisfactory results must await transport|| tion to the laboratory. However, the use of permanent standards, and possiblygM accelerator, would improve the results obtainable at the time of sampling. In''/ present stage of development the method is satisfactory only in the laboratofl, where results may be determined with a spectrophotometer and compared 'wit] |||&have been made.25 The use of a free flame for the combustion analysis ;s,-iof.vapors was introduced by Patty, Schrenk, and Yant.28 A similar allowed by Winter,27 using a lamp method. A sulfur lamp apparatus Isei lljPipth and Stross28 to determine sulfur and chlorine in gasoline, and ffi^ibeen used for the determination of various organic chlorides in )ij|uids. Elkins29 scrubbed carbon tetrachloride from the air with amyl fiiurned it in a modified sulfur lamp. In all of these methods combus- ggund to be quantitative. The percentage absorption of the products of janfosaries with the type of apparatus employed and may be seriously low |p|ing concentrations on the order of 0.2 per cent or higher, and when ra^ojume of absorbing liquid. In the combustion-tube method at least *' fij|quired to collect the sample, after which the combustion products 1, into a suitable flask and taken to the laboratory for titration, Sffijpeiand rapid. The sulfur-lamp method requires more time since it l|||p)ihg the vapor from the air before it can be burned in the lamps, results obtained with standard solutions, due regard being taken of the time fh| ------------X)7lLCN"D''PIST0Nt'PUMPrEUER''SYRrNGE7"A`ND'RUBBER-BIJI:B-------- COLLECTION DEVICES . .5 Hand piston pumps and rubber aspirating bulbs have been used for colleclnm samples. These methods, which aim to avoid the more cumbersome, ortho" augbion-methods are specific only for the class of halogenated vapors and ||jj||jes;r.bromides, or iodides), and organic halogens cannot be differ- mcjmaa'cid halogens. uhTesriSnipled through "a filter to remove acid Ipods-employing glass apparatus are not applicable to the determina- ||mdMj'because the fluoride combustion products attack glass. These ^methods obviously give an integrated result for the entire period of methods of sampling, may involve pulling the atmosphere through indicatm| granules, such as in the MSA hydrogen sulfide detector, the aromatic hydrocaSm" detector, and the NBS carbon monoxide indicating tube.21 Indicator pape^" scrubber may also be used. The pump may be calibrated and the sample measfjtg by the number of piston strokes. Luer syringes have been used for meastifm^ atmospheric samples and as reaction chambers for the determination of oxygei||| and also as a comparison chamber in the determination of nitrogen dioxide, " examples q|:-ilii^5.Jggs-of;sampling Have, as their .purp'ose the keeping equipmentr'tb-h'imimtiium and also the obtaining of direct results: hr theffii Accuracy in some instances may, and in others may not, equal that obtamea|ljj| longer and more cumbersome methods. " FrHTGolcImim and D."E.~KusEing, J. IrTd. Hyg. Toxicol., 25, 164, 105 (1913). ~ :i "M. Shepard, A Preliminary Report of the NS. Colorimetric Indicating Gelfil^ Rapid Determination of Small Amounts of Carbon Monoxide. Natl. Bur. Standards, June| 1946. "Y. Henderson and L. A. Greenberg, J. Am. Med. Assoc., 96, 1474 (1931). DF. A. Patty and G. M. Petty, J. Ind. Hyg. Toxicol., 25, 361 (1943), fcY.; goffinterest to compare sets of figures obtained independently by two if)erators, one with the Willson combustion apparatus, for halogenated ^fed.one with the Zeiss gas interferometer. The samples were taken te period in a room of a plant where carbon tetrachloride was be- vH&mrbottles onto a table top. The samples were drawn through a ^*pS[ffl$epsion on the combustion tube of the ,sWillson apparatus, the Y ...............* " ~~ =......... fflljum'titative Organic Microanalysis. TranB. by Tylemann. 2nd ed., Blakiaton, 924jf;'rv SJlAi'^ff&isbofff,./nd. Eng. Chem., Anal. Ed., 7, 428 (1936) ; B. D. Tebbens, J. Ind. Hyg. A' ettorlmd, Determination of Chlorinated Hydrocarbons (.EExxccept a{1 nH'J.'jninois^Stato Dept, of Health, Div. of. Industrial-Hygiene.-GChhiicago;-111.; Health Repts., 56, 102 (1941). _gSftSiH. Schrenk and W. P. Yant, Ind. Eng. Chem., Anal. Ed., 4, 259 (1932). Eng. Chem., Anal. Ed., 15, 671 (1943). ' lygftpSfeM. J- Strosa, Ind. Eng. Chem., Anal. Ed., 5, 85 (1933). ,, W K- Hobby, and J. E. Fuller, J. Ind. Hyg. Toxicol., 19, 474 (1937). i1 ' 1 >' i v; ^ l35Ss,,.,.