Analysis of Lithium Metal, Hydride, a n d Hydroxide for Nickel, Copper, Silicon, Iron, Chromium, Aluminum, a n d Hydroxide SIR: Both naturally occurring lithium isotopes are very important in nuclear technology. Because minute quantities of other elements as impurities may hamper nuclear reactiions, analytical procedures to determine these elements a t micro quantity 1cvt.ls were needed. Although wrll knon n inethods are reported in the literature., it was necessary t o adapt thew proceduws to this matrix. Sandcll discusses sevrwl methods for t h r determination of nickel (11) and coilper (9). His dime1,hylglyoxine extraction method is tiatisfactory for nickel dctermination ( d : , and the residue from this extraction may be used for the determination of copper. The carhonate procedure can be adapted t o determine copper, if tht. copper carbonate is c,\tracted with isoamyl alcohol
complex (IO). For colored solutions or solutions containing a high concentration of impurities, the iron may be concentrated and separated by carrier precipitation with zirconium hydroxide (6)*
(6)* Chromium may be determined by using diphenylcarbazide (14) in the range of 0.1 to 10 y. Since the presence of lithium ciLuses cloudiness in the colored solution, chromium is determined b y wparuting it from the lithium by carrier lmxcipitation with aluminum hydroxide (3) * A simple method for the determination of silicon up to 100 y is the ammonium molybdate procedure (15). It was necessary, hoirever, to follow a rigid order of addition of chemicals (4) for this method t o work. Iron may be drtrrmined photometrically a t a controlled pH by reducing all iron to the ferrous state with hydroxylamine hydrochloride, and then forming t h r ferrous o-phenanthroline
Aluminum may be determined colorimetrically in the range of 0 to 20 p.p.m. with aluminum reagent (13). Lithium influences the slope of the standard curve, but does not interfere if both samples and standards are prepared with the same lithium ion concentration ( 7 ) . Hydroxide in lithium hydride (8) may be determined by reaction of the sample with benzoic acid-methanol solution and titration with Karl Fischer reagent. By a simple calculation with the data from this titration the amount of oxygen may also be determined. However, the amount of carbonate must be known for accurate analysis because of the reaction: 2+COOH
+ LisCOa - 2+COOLi + H2O
+ CO,
The same procedure should work for the determination of oxidcs in lithium metal. Sax (12) adopted a method of Eberle’s ( I ) , in which he uses a salicylic acid-pyridine mixture instead of benzoic acid to determine oxygen in lithium. However, both procedures have large blank titrations, while no blank is required for the benzoic acid procedure. Both ignore the presence of carbonate ion.
G. J., ANAL. CHEM.27, 1431 (1955). ( 2 ) Friedman, H. A,, “Analysis of Lithium Metal, Hydride, and Hydroxide,” I, “Colorimetric Determination of Nickel,” Office of Technical Services, Y-973 (Del.) (Nov. 15, 1952, declassified Dec. 3, 1957). ( 3 ) Zbid., 11, “Colorimetric Determination of Chromium,” Y-968 (OTS) (Iiov. 17, 1952, declassified Dec. 3, 1957). (4) Zbid., 111, “Colorimetric Determination of Silicon,” Y-962 (Del.) (OTS) (Nov. 15, 1952, declassified Dec. 3, 1957). (5) Zbid., IV, “Photometric Determination of Copper,” Y-1059 (OTS)(March 21, 1953, declassified July 15, 1957). ( 6 ) Zbid., V, “Photometric Determination of Iron.” Y-1060 (Del.) (OTS) (March i, 1953; declassifie‘d Dec.:3, 1 9 5 i ) . ( 7 ) Ibzd., VI, “Colorimetric Determination of Aluminum,” Y-1057 (Del.) (OTS) (Jan. 15. 1953, declassified Dec. 8, 1957j. (8) Friedman, H. A,, “Determination of Hydroxide in Alkali Hydrides,” Y-978 (Del.) (OTS)(July 6, 1953, declassified Dec. 3, 1957). (9) Sandell, E. B., “Colorimetric Determination of Traces of Metals,” 2nd ed., pp. 304-6, Interscience, P\ew York, 1950. (10) Ibid.. DD. 375-7. ( i i j Ibid.; Pp. 469-74. (12) Sax, X . I., Steinmetz, H., “Dete;; mination of Oxygen in Lithium Metal, Oak Ridge Natl. Lab., ORNL-2570 (Oct. 15, 1958). (13) Snell. F. D.. Snell. C. T., “Color‘ imetric ’Methods of ilnalvsis.’” Vol. I: 3rd ed.. DD. 248-50. Van ’Nostrand: New YdrCLl949. (14) Zbid., pp. 294-6. (15) Zbid., pp, 692-5. H. A. FRIEDMAS
LITERATURE CITED
(1) Eberle, A. R., Lerner, hl.
K., Petretic,
Oak Ridge National Laboratory Oak Ridge, Tenn.
Determination of 1,3- and 1,4-DimethyIbenzenes and Acetophenone S. H.
HASTINGS and D. E. NICHOLSON Humble O i l 8 Refining Co., Baytown, l e x .
CS-1 13
I
Component --~
No, 1
Nome
I
1
Acetophenone
benzene
Formula
,c i
sH 8
0
Slit Range
Accuracy
X or Y B. 1.
%
70
Pis.
(mml
AX o r Av
Concn. g/liter length mm
Insfrument: Perkin-Elmer Model 1 12, NaCl prism Sample Phase: Solution in carbon disulfide Cell Windows: NaCl Absorbonce Measurement: Calculotion:
Base line-
Inverse matrixGrophical-
P o i n t X Successive a p p r o x . 2
Relafive Absorbances-Analytical Mafrix: 1 5 . 9 2 ~ 0.180 0 . 0 3 5 ~ 1 .oo 5.92~ 11.42~ ~ _ _ Componenf f X 1 0.341 0.000 1 3~0.5 1 1 . 4 2 ~ 0.550 0.020 2 0.000 0 . 0 5 2 ~ 1 .oo ~0.000 3 0.000 1 z k 0 . 5 1 2 . 5 9 ~ 0.630 Maferial Purity: 1,3and 1,4-dimethylbenzenes, 99.5%; 0 . 0 5 7 ~ 1.00 98%
0-100 rk0.5 0-100
0-100
VOL. 32,
NO.
12.59~ 0.001 0.002 0.278 acetophenone
1, JANUARY 1960
137
