Gravimetric Determination of Germanium in Silicon—Germanium Alloys

An accurate method is given for the gravimetric deter­mination of germanium in silicon-germanium alloys. Silicon is separated as silicon fluoride; citric acid is used to prevent the loss of germanium as a volatile fluoride.

K. L. CHENG and B. L. GOYDISH, RCA Laboratories, Princeton, N . J .

Anal. Chem. 35, 1273 (1963)

The Determination of Oxygen in Lithium

The method involves solution of lithium in liquid am­monia followed by filtration of the resulting solution and titration of the insoluble residues. Various methods for handling the sample prior to analysis are discussed. The results of the method are compared (applied to other alkali metals) with those obtained by the amalgamation tech­nique.

R. J. JAWOROWSKI, J . R. POTTS, and E. W. HOBART, Pratt & Whitney Aircraft—CANEL, Middletown, Conn.

Anal. Chem. 35, 1275 (1963)

Separation of Titanium from Rare Earths, Beryllium, Niobium, Iron, Aluminum, Thorium, Magnesium, Manganese, and Other Elements by Cation Exchange Chromatography

A systematic study indicates the absorbing of cations with AG 50W-X8 resin in sulfuric acid permits a good separa­tion of titanium from many other ions. The described method gives satisfactory results when up to 5 meq. of beryllium or 10 meq. of the other ions are present with titanium.

F. W. E. STRELOW, National Chemical Research Laboratory, South African Council for Scientific and Industrial Research, Pretoria, South Africa

Anal. Chem. 35, 1279 (1963)

Applications of High Resolution Nuclear Magnetic Resonance Spectrometry to the Identification and Quantitative Analysis of Nonionic Surfactoints

The type of hydrophobe and the ratio of hydrophilic to hydrophobic portions of the molecule were identified. In addition, in most cases, average values of the molecular weight of each portion of the molecule were determined. The method is applicable to samples which are mixtures of homologs; 0.05 ml. of sample is adequate.

P. W. FLANAGAN, R. A. GREFF, and H. F. SMITH, Research and Development Department Continental Oi l Co., Ponca City, Okla.

Anal. Chem. 35, 1283 (1963)

Determination of Submicrogram Quantities of Manganese, Sodium, and Copper in Natural Diamonds by Neutron Activation Analysis

Gamma-scintillation spectrometry was used to detect the 0.85-m.c.v. gamma emission of MnM, the 1.37-m.e.v. gamma emission of Ν a24, and the annihilation radiation due to the positron emission of Cu84. Specimens weighing from 5 to 100 mg. gave 0.002 to 0.09 p.p.m. of Mn, 0.05 to 0.4 p.p.m. of Na, and less than 0.0004 to 0.9 p.p.m. of Cu.

E. C. LIGHTOWLERS, Wheatstone Physics Laboratory, King's College, University of London, Strand, London, W. C. 2, England

Anal. Chem. 35, 1285 (1963) Circle No. 25 on Readers' Service Card

VOL. 35, NO. 9, AUGUST 1963 · 17 A

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