BRIEFS Analysis of Mixtures of Antimony and Bismuth Tellurides Containing Selenium and Iodine Te is determined gravimetrioally as Te0 2 . Bi and Sb are determined by step E D T A titrations in the presence and in the absence of tartrate, which can mask Sb. Se is determined photometrically with 3,3'-diaminobenzidine, and I is determined photometrically by measuring the turbidity of Agi in an ammoniacal medium after a simple distillation. K. L. C H E N G and B. L. G O Y D I S H , R C A Laboratories, Princeton, N. J. A n a l . C h e m . 3S, I965
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Determination of W a t e r in Red Fuming Nitric Acid by Karl Fischer Titration
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The method determines water in red fuming nitric acid samples containing 0 t o 15% nitrogen dioxide. T h e pooled standard deviation (40 degrees of freedom) is 0.052% absolute and the error is 0.042% absolute. E. A . BURNS and R. F. M U R A C A , J e t Propulsion C a l i f o r n i a Institute of Technology, Pasadena, C a l i f .
Laboratory,
A n a l . C h e m . 35, 1967 ( 1 9 6 3 )
Determination of Microgram Amounts of Total Sulfur in Rocks. Rapid and Accurate Analysis by a Combustion Method The method gave good results with National Bureau of Standards standard samples. Application t o several acidic, basic, and ultrabasic rock samples (sulfur contents 0.01 t o 0.8%) gave results superior t o those obtained by the conventional gravimetric barium sulfate method. J . G . SEN G U P T A , Ontario, C a n a d a
Geological
Survey
of
Canada,
Ottawa,
A n a l . C h e m . 35, 1971 ( 1 9 6 3 )
Paper Chromatography of Monohydroxyphenols in Vanilla Extract
contact your local laboratory equipment dealer or:
Techne (Princeton) Ltd., 6 6 1 , Brunswick Pike Princeton, New Jersey, Area Code 609:921-2817 Circle No. 180 on Readers' Service Card
18 A
.
ANALYTICAL CHEMISTRY
Various methods of separation, concentration, and purifi cation were studied. A spray of Millon's reagent reacted with monohydroxyphenols on the paper, giving colored compounds. Of the seven phenols separated, three were identified in this study, while three had been reported previously. M. H . A N W A R , land C i t y , Ν . Υ .
Research Department, Pepsi-Cola C o . , Long Is
A n a l . C h e m . 35, 1974 ( 1 9 6 3 )
