ient becau3e of the difficulty of drawing out capillaries of the right dimension. Proper Amounts O F Reagents Used in Combustion Tube. If cuprous oxide is taken a‘ t h e probable ieaction product in t h e coinbustion instead of the usually considwed cupric oxide. only 50 mg. of coplx’r is theoretically nece’sary t o combine n i t h 4.5 nil. of oxygen. Furthermorf,, a favorable decrease by l to 1.5 nil. in the oxygen volume proceeds froiii the oxygen uptake by the buriiing sample. Consequently the recommended amount of 100 mg. of copper p-okidcs an ample niargin of safety. In connection n i t h the reagent mixture, a siniilar iliargin of safety is provided for in the amount recommended. For TT ork a t the dei~imilligram level, 100 nig. of the niilture is suggested, although as little as 50 mg. has been found sufficient t o ab-orb all carbon dnoide generated in the combustion of lauric acid control m i p l e s u p to 1 5
mg. On the other hand, incomplete water absorption was observed when sample weights of the same test material exceeded 1 mg. Here small spots of condensed water were discovered between the inside wall of the capillary and the mercury. Consequently, for samples under 1 mg. the recommended amount of reagent mixture mas increased to 100 mg. for security. Empirical Correction of Analytical Results. 21 nuniber of analyses were cairied out with >creral standard substances t o determine the distribution of error ( F i g ~ i r 3). e hlthougli t h e de\ iatiori usunlly icll m-it!iin Pregl’s limits for nitrogen prrcentages u p to 2075, it n-as more serious in the case of thiourea (36.837,) where the analytical values were frequently outside the lower limit of acceptability. X possible explanation for low results in the case of liigher nitrogen percentage may lie in significant occlusion of nitrogen gas by the porous reagent mixture and the
copper gauze. The absolute error caused by this effect should be proportional t o the nitrogen content of the sample. From the rough estimation in Figure 3, a relative correction of +1%, shown by the dotted line, is indicated for the samples analyzed. ACKNOWLEDGMENT
The author thaiiks IT’. J. IGrsteii for valuable suggestions. LITERATURE CITED
(1) Hozumi, K., Kirsten, W. J., ASAL. &EM. 34,-134 (IgB‘S). ( 2 ) Kirsten, IT. J., 2. Anal. Chrin. 181, 1 (1961).
(3) Kirsten, W. J Hozumi, Iphorus,potassium, and sodiiini; 250 of s:licon; 100 each of rnagnesiuin, vanadiuin, chroniium, and Iiickel; 50 each of manganese, lead, biqmuth, niolybdenuni, tin, and copper; 25 each of calcium ar.d lithium, 5 each of cadmium, silver, and boron. Standard sample of EeO, KBL 72-1, contains the folloiving, in p.p.m.: 2000 each of iron, aluminum, and silicon; 1000 of calcium 500 each of :lickel, manganese, magnesium, chromium, and zinc; 100 of copper; 50 each of lead and molybdenum; 20 of cobalt; 10 of silver; 5 each of boron, cadmium, and lithium. Reproducibility and Accuracy. T h e reproducibility of tfhe general procedure was studied by carrying 10 solutions, each containing 700.0 pg. of tungsten, through the general procedure. The relative error found n-as 0.26%, and I
Table II.
Determination of Tungsten in Various Standard Steel Samples
Tungsten KBS standCertified ard value, Mean, sample Type of steel 7c Found, yo %h 73% Cr 14 0 . 091a 0.96. 0.96. 0 . 97, 0.96 0.96 Cr 18, S i 11, S b 0 8,Ta 0 02 0.11 0 10; 0 11; 0 11, 0.11 123s 0.11 123b 0.18 Cr 19, Xi 11, S b 0 8 , Ta 0 2 0.18 0 180, 0 187 132 Cr 4 6.29 6 29, 6 22, 6 22: 6.37, 6 30 6.36 132a Cr 4, 110 4, 1- 2 6.16 6.20 6 16, 6 15 1107 , Cr 4,1- 2 1.s1 1.82 1 80, 1 82, 1 81 134 134a 110 8, Cr 4, 1- 1 2.04 2.00 2 06, 2 03 153 1.59 310 8, Co 8, Cr 4, 1- 2 1 .68 1.60; 1.60, 1.57, 1 , 6 0 l5S Cr 0 5 . W 0 5 0.517 0.517 0.525. 0.510. 0,616 4 *2 +tainless steel 0.08 0.087; 0.086’ 0.086 443 Spectrographic 0.09 0.087 0.087, 0.087 444 0.17 0.177, 0.176 0.176 Standards Three values reported: 0.094, 0.092, 0.087, determined by a-benzoinosirne-hydroquinone procedure. Table 111.
Comparison of Results for Tungsten in Zirconium and Zircaloy Samples b y Thiocyanate, Dithiol, Hydroquinone, Spectrographic, and 8-Quinolinol Procedures
Material analyzed Zircaloy S B P 360 Zirconium SBS 1210 Zirconium S B S 1211 Zircaloy S B S 1213 Zircaloy SBP 1214 Zircaloy XBS 1215
Table IV.
1I:iterial
(3;
Thioanate
Tungsten, p.p.m. HydroSpectrographic quinone
Dithiol
21
12
7, 9, 8,s
10
15, 15, 14
4, 4, IG
3 , IS
8, 8
30
5, 5) 5
X8, 42
31, 33
30
38, 35, 35
7 , 8 , 16
4> s
10, 10
15
6, 6, 6, 6, 6, 6
32, 4 4
33, 38, 7
40, 46, 41, 4G
50
34, 35
300, 312, 304
261
2\37, 258, 263,
100, 260, 459
262
;39, 4(J,
31
264
Recovery of Added Tungsten to Zircaloy, Uranium, and Beryllium
XBL 95-1
Present. p.p,m. metal basis 31o co Cu 4 ... 26 304 ... 26 1004 1000 1026: 504 ... 26 504 ... 26 1050 ... -50 ,550 ... 50 5 0
...
Be0
1050
20 2020
analyzed
Zircaloy SBR 1213 U3Oa
S B L 72-1
8Quinolinol
2050
the relative standard deviation n-as iO.SO%. The mean value found for 10 determinations on a zircaloy sample, zircaloy NBS-1215, was 262 p.p.ni. with a relative standard deviation of =t1.91%. Five determinations mere made on a standard steel sample, NBS-132, certified as 6.29%. The relative error found was O.lGOj, and the relative standard deviation, =t1.26%. The method is precise and accurate. LITERAITURE CITED
(1) Carlson, A. R., Banks, C V., AXAL.
CHEX 24, 472 (1952). (2) Eberle, A. R., Lerner, M. W.,Ibid., 34, 627 (1962).
50
100 2100
Tungsten, p.p.m. metal basis _Present ... 31 31
106 -106 25
100
500 50 400
Found, 6 31 34 106
Difference
406 27 101
498 52 404
...
0
+3
0 0
+2 fl -2 +2
$4
(3) Fritz, J. S.,Garralda, B. B., Karraker, S. X., Ibid., 33, 882 (1961). (4) Hillebrand, W.F., Lundell, G. E F , Bright, H. A,, Hoffman, J. I., “Applied Inorganic Analysis,” 2nd ed.. p. 689, Wiley, Xew York, 1953. (5) Machlin, L. A., Hague, J. L., J . Res. Natl. Bur. Std. 59, 415 (1957). (6) Peng, P. Y . , M.S.thesis, University of Minnesota, Minneapolis, Minn., 1962. (7) Sandell, E. B., “Colorimetrtic Determination of Traces of Metals, 3rd ed., Interscience, Sew York, 1959. (8) Taylor, R.P., Ph.D. thesis, Princeton University, . . Princeton, X. J., 1954. RECEIVEDfor review October 11, 1962. Accepted March 11, 1963. Presented a t the Sixth Conference on Analytical Chemistry in Nuclear Reactor Technology, Gatlinburg, Tenn., October 1962. V O L . 35, NO. 6, MAY 1963
673
