range is critical; allouing the teniperature to escecd the limits causes low reproducibility and overheating brings about high reagent blanks as nell. This method has been used routinely in this laboratory for the past 6 months on clinical blood and urine samples with satisfactory results. ACKNOWLEDGMENT
This work was aided by a grant from the Michigan hlemorial Phoenix Project. The interest and encouragement of James L. Wilson are deeply appreciated.
LITERATURE CITED
(1) Barnes. R . H., Wick, il. \I7,)J . Biol. Cheni. 131, 413 (1939). (2) Behre, J. Ah.> Ibid., 136, 25 (1940). 1 3 ) Behre. J. A.. Benedict. S. R.. Ibid.. 70.
487 (19’6).
’
14) Crandall. L. -i.!Jr., Ibzd., 133, 539
(1940).
(5, Greenberg, L. A,, Lester, E)., Ibid., 154, 177 (1944). (6) Klendshoj, S . C., Feldstein, Milton, Can. J . X e d . Technol. 17, 74 (1985). (71 \ , Lauersen. Fritz. Klin. Wochschr. 15. 339 (1936): 18) RIarenzi. A. D.. Braemer, E. S.. Pubis. inst. invest. &ropuiK Linin. naci, litoral (Rosario, Ary.) 17, 140 (1953). (9) ;2licharls, G. D., Margen, Sheldon, ~,
Colorimetric Determination of SIR: The Griess Ilosvay method has been used in air pollution work to determine nitrogen dioxide in laboratory and field operations and has been adapted for use in automatic instrunientation ( 5 ) . In this latter investigation ( 5 ) it was shown that alkyl nitrites also react n i ‘ h the reagent in the automatic nitrogen dioxide analyzer used. It appeared of interest to determine the reactivity of the alkyl nitrites directly without having to consider absorption efficiencies. The amount of reaction of n-butyl nitrite, krt-butyl nitrite, n-amyl nitrite, and isoamyl nitrite on a micromole basis was determined for comparison a i t h the reactivity of sodium nitrite and nitrogen dioxide (8). The concentrations ranged between 0.07 and 0.7 micromole per 10 ml. of Table 1.
Colorimetric Results with Alkyl Nitrites
llethod
Absorbance Units/ pmole Alkyl Xitritea Alkyl Prepara- .hbsorbance Units/ tion pmole KaNOs Nitrite n-Butyl A 0 64 zk 0 04 B 0 79 =!= 0 05 C 0 79 zk 0 0 7 tert-Butyl B 0 70 i 0 03” n-Amyl B 0 81 i 0 OAC C 0 91 i o 04 Isoamyl A 0 77 i 0 06 B 0 74 i 0 04 C 0 79 0 03 A = untreated, B = atmospheiic distillation, C = vacuum distillation. a Standard deviation given after average values. * Average of three determinations. c Average of two determinations. of
314
ANALYTICAL CHEMISTRY
~
Alkyl Nitrites
solution. The reproducibility of the results ranged from =!=5 to &lo% for a given sample of an individual alkyl nitrite (Table I). Saltzman has reported that the reactivity of nitrogen dioxide compared nith inorganic nitrite is in the ratio of 0.72 to 1. Patty and Petty found this ratio to be 57 2.6% ( 1 ) . Thomas (4) found it to be 0.9, using the automatic analyzer (@, for which the ratio drifted upnard towards 0.9 over a period of months. Changes in the gas-liquid contactor column with time may account for this behavior. The difference in the two former values may be due to the use of S-(1-naphthyl)ethylenediamine dihydrochloride rather than 1-naphthylamine by Saltzman and a higher concentration of sulfanilic acid. Saltzman’s data ( 2 ) indicate an increase in the ratio with increasing sulfanilic acid concentration. Table I shons that the alkyl nitrites react to about the same extent as nitrogen dioxide. Distillation, particularly vacuum distillation, increases reactivity through improved purity of the alkyl nitrites. Undoubtedly, a portion of the diffcrence in the observed ratios from unity is the rtsult of appreciably less than 100% purity in the alkyl nitrites. High purity is difficult to achieve and maintain, bccause of the instability of the alkyl nitrites to heat and light. It has been suggested that the ratio for nitrogen dioxide and alkyl nitrites may involve a reverse oxidation-reduction system (4). A comprehensive study of the kinetics of the reactions involved would be extremely useful. The results obtained in this inyestigation and elsewhere indicate that the method u s d for nitrogrn dioxide is not
*
Liebert, Gei:tld, Kinsell, L. \I-,, J . Clin. Invest. 30, 1483 (1951). 110) Nadeau. GUT,,Can. Med. .-lssoc. J . 67, 158 (1952). ” ’ (11) Ra paport, F., Baner, B., J . Lab. Clin. s e d . 2 8 , 1770 (1943). (12) Rutman, J. Z., Ibid.,*41, 648 (1953). ., Z . klin. X e d . (13) Schvivenkenbacher, 1% 134, 325 (1938). (14) Sobotka, Harry, Carr, J. J., “Anriual Review of Medicine,” Vol. 6 , p. 260, -4nnual Review, Stanford, Calif., 1955. (15) Tsao, 11.E., Baumann, bl. L., Wark! Shirley, . ~ X A L .CHEM.24, 722 (1952). (16) Jan Slyke, D. D., J . Biol. Chem. 32, 453 (1917). (17) Weichselbaum, T. E., Ibid., 140, 5 (1941). RECEIVED for review March 26. 1958. .iccepted September 12, 1958.
specific but responsive to all compounds, inorganic and organic, containing the 0-N-0 group. These compounds include the acyl peroxy nitrite found in the Los Angeles type atmospheres by infrared investigations (3). Furthermore, the complex reaction products formed by the reaction of nitric oxide and nitrogen dioxide with olefins often groups. Concontain reactive O--h’-O sequently, methods are needed to differentiate nitrogen dioxide from organic nitrites. EXPERIMENTAL DETAILS
The alkyl nitrites included n-butyl nitrite, tert-butyl nitrite, n-amyl nitrite, and isoamyl nitrite from commercial sources. These nitrites were subjected to atmospheric and vacuum distillations during various stages of the investigation. A number of the lots of alkyl nitrites were dried over calcium chloride. The solutions for the colorinictric determinations Fvere prepared by dissolving 1 ml. of the alkyl nitrite in 75 ml. of glacial acetic acid and diluting to 250 ml. with distilled water. One milliliter of this solution was diluted to 100 ml. with distilled ivater to make the necessary solutions in the microgram range. An aliquot of test solution nas added to 10 nil. of a reagent prepared by dissolving 5 grams of sulfanilic acid in nearly a liter of tvater containing 140 ml. of glacial acetic acid, adding 20 ml. of O.lyo -Y-(l-naphthyl)-ethylenediamine dihydrochloride solution. and diluting to 1 liter ( 2 ) . After 10 minutes the color wab read in a Beckman Model D r spectrophotometer a t 550 nip. The stability of 0.4% tert-butyl nitrite in acetic acid-water solution n as followed by means of its spectruni in the 3000- to 4000-A. region using a Cary Model 11 spectrophotometer.
Solutions kept at room temperature showed about 12% lrss ahsorption after 100 to 200 minutes. Solutions kept at iced mat,rr temperatures showed 4% decrease in ahsorption after 100 minutes, 8% decrease after 200 miniitrs, and 21% decrease after 20 hours. An 0.004% tert-butyl nitrite solution in acetic acid water was followed with Grirss reagent. After 4 hours a t 0" C. no change was observed, hut after 20 hours a 15y0 decrease was found. These results indicate that solutions in the range of several tenths of 1% can be kept for an hour or two at iced water temperatures without appreciable dccomposition, hut for only a very
limitrd time a t room temperature. At low concentrations, solutions a t iced water trmprraturcs are stable for many hours. An undiluted alkyl nitrite was followed for several days after redistillation without any indication of decomposition. All alkyl nitrite solutions were kept in brown bottles or actinic flasks to prevent decomposition by light. If the working solutions had to he used for extended periods (more than 0.5 hour), they were kept in iced water baths. The undiluted alkyl nitrites were stored in brown bottles in the freezing compartment of a refrigrrator.
LITERATURE CITED
(1) Patty, F. A,, Petty, G. M., J . 2nd. Hyg. Tozicol. 25, 361 (1943). (2) Saltaman, B. E., ANAL. CHEDI. 26,
1aAa-w itask) "_ \_"".,_ (3) Stephens, E. R., et al., J . Air Pollution Control Assoc. 6, 159-65 (1956). (4) Thomas. M. D.. Stanford Research Institute, 'private iammrmicrttion. (5) Thomas, hZ. D., et al., J . Ai7 Pollution " . I
Lommnnlc"
9 1 r l0Ll"Tl""
rrogmln
Robert A. Taft Sanitary Engineering Center U. S. Public Health Service Cincinnati 26, Ohio
r 178.
Tetrasodium Enneagermanate, Na,Ge,O,,, Tetragonal Form J. F. WHITE, E. R. SHAW, and JAMES F. CORWIN, Departments of Geology and
...._..,,
Ch-mirtrv _I._
_.."..
-...-
A n t i"_,. n r h Cnllenn V-llnu S n ~...y-, i n n c nhin -"..-y-, , _r.
.I....
A. PABST, Department of Geology, University of California, Berkeley, Calif. unEnRAL ciystals of prrviouslv unNa4Ck!oO?o(Figure 1) hydrothrrmally by reaction of gcrinanium dioxidr-sodium hydroxide mixtures and aiitrr at 200" C. and 12 ntin. llrtaila of the prcparation h a w hrrn givrn (5),but the ?ompound was referred to as sodium tetragrrmanatr. Prrpamtions of sodium trtmgrrmanntr Iiavc lirrn mrntionrd XISO by So!\-otny and n'ittmnnn ( 1 , 8) and Schrmrtz and Hrinrirh (S), but no description of the matrrial could be found. The chrniir:il formula, Na4Geo02., was rhosrir in prefrrencc to that of the tetragennanntr (Na2Ger09) primarily on the basis of unit crll and density data. Density mcasunmrnts, nintlc by both pycnometer and Rerman halnnce, agree well with density calculatrd for the assumed composition (4.268 calculated and 4.26 mcasurrd). On the other hand, if the tetragrrmanate is assiimrd, a largr disrrrpancy exists hetrr-een thr ralrulntrd density of 3.85 and the ohsrrvrd density of 4 . 2 6 Further support for thr choice was given by synthesis experiments. The compound was made from a melt of the "correct" composition, GrO,/NhO = 4'/,/1. KO significant amounts of extra phases iverc drtrcted optically in the coxrsrly rvstallinc matrrial or by
E described were prepared
b
infrared analysis. Mixtures of GeOd Na10 in ratios of 4/1 and 4'/dl were also trird. In both of these (hut not in the 4ll2/1 mixture), examination of infrarrd spectra, indicated carhonatr, which suggested excess Na20. Chrmicnl analysis (4) gave the following avrrage veight percentage: Na20, 12.2%; GPO?,87.5yo;H,O, 0.3'%. Ccll dimrnsions and space group li-crc drt,rrminrd from single crystal diffrartion pattrrns. hkQ, hkl, hO1. hll, and h21 precession pattrrns and h01 TTeissmherg and a-axis rotation patterns were taken with Cu rndiation. hkO. hkl, hk2 precrssion and h01 Wrissenherg patterns Tvrrc tnkrn rrith 110 radiation. Dimrnsions wrre drtrrmined from the precession patterns whirh bad been corrected for shrinkagr and the instrument calibratrd by mrans of a standard quartz crpstal. Thc prrcession piLtterns reveal the Lane symmrtry 4 / m . Systematic absences leave only hkl with h k I = 2n. 001 only nith I = 4n, and hk0 only with h = 2n and k = 2n. This unequivocally estahlishrs the space group as C,P - 14,/n.
Hahit. A. Stuhhy prisms, 11101 dominant; or ( 1 0 0 ) and (1101. Prism ends are somewhat rounrled, presumahly flat pyramidal forma ratlicr than !001 1.
-I
+ +
CRYST.41, ~ f O R P H O L O O I
System. Tetragonal, Class. 4 / m .
Figure 1 . Single crystals of tetragonal tetrasodium enneogermanate showing two habits Sire of the prismatic ~rystolsobovt 30 microns, pyramidal crystals about 40 microns in diameter
VOL. 31, NO. 2, FEBRUARY 1959
315
