Detection of Lanthanum, Yttrium, and Ytterbium from Spark in Flame Spectra 0. S. PLANTINGA
AND
C. J. RODDEN, Washington Square College, New York University, New York, N. Y.
T(I),
HE simplified spark in flame spectra method of Hultgren
in which the concentration of praseodymium was 1.5M , showed a limit of detection of lanthanum only one-tenth of the value of pure lanthanum. A rough estimate of the amounts of the three elements may be made b y examining the spectra of successive known dilutions of the sample until the bands disappear. The method of detection outlined is economical and rapid, about 0.1 cc. of solution being used in a test requiring about a minute. The value of the method as applied to laboratory samples of the rare earths is illustrated b y the examination of a sample of c. P. erbium which was found to contain 40 per cent of yttrium. The method has been successfully applied, in a few cases, in following the fractionation of rare earths.
previously reported b y the authors (4), has been applied to the detection of lanthanum, yttrium, and ytterbium in rare earth salts. LundegPrdh (9) detected neodymium down to 0.01M by a flame spectrum method, and Piccardi and Sberna (3) found limits of 0.01 per cent for lanthanum oxide and 0.001 per cent for yttrium oxide, using molecular flame spectra. The method employed by the authors involves the visual spectroscopic examination, with a hand spectroscope, of a spark discharge in an ordinary gas flame in which the chloride, nitrate, or acetate solution of a sample is volatilized. The three elements studied were detected by the appearance of the following band heaods in the spectra: for lanthanum, 4372,04418, and 5600 A.; for ytirium, the group 5892 to 6200 A.; and for ytterbium, 5700 A. The limit of detection, based on the dilution of a solution of each element of known strength, is in each case about 0.0001M , although for concentrations lower than 0.001 M , the spectra flashed unsteadily. The limit of detection is affected b y the presence of other rare earths or of large amounts of sodium. For example, a mixture of lanthanum and praseodymium chloride solutions,
Literature Cited (1) Hultgren, J. Am. Chem. SOC.,54, 2320 (1932). (2) LundegPrdh, H., Svensk Kem. Tid., 42, 51 (1930). (3) Piccardi, I. C., and Sberna, A., Atti acad. Lincei, 15, 83, 309 (1932). (4) Rodden, C. J , and Plantinga, 0. S.,Phvs. Rev., 45, 280 (1934).
RECEIVED December 17, 1935.
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