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Transient Phenomena a t Glass Electrodes An experimental m e t h o d allowing electrode exposure t o a reproducible change in ionic environment within a few milliseconds is described. T h e emf vs. time character istics of two types of cation-sensitive glass electrodes under varying solution conditions are summarized. G. A . RECHNITZ, Department of Chemistry, State University of New York, Buffalo, N. Y. 14214, and G . C. KUGLER. Department of Chemistry, University of Pennsylvania, Philadelphia, Pa. 19104 Anal. Chem. 39, 1682 (1967)
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Spectrophotometric Determination of Atmospheric Sulfur Dioxide Two improved methods for t h e determination of sulfur dioxide are reported. I n M e t h o d A, a final rose-red color develops at near optimal p H 1.6 ± 0.1 at 548 ναμ. I n M e t h o d B , a magenta color is developed at p H 1.2 ± 0.1 read at 575 ναμ. Standard deviation a t t h e 9 5 % con fidence level is 4.9% for both methods. F. P. SCARINGELLI, B. E. SALTZMAN, and S. A. FREY, National Center for Air Pollution Control, Bureau of Disease Prevention and Environmental Control, Public Health Service, U. S. Department of Health, Education, and Welfare, Cincinnati, Ohio 45226 Anal. Chem. 39, 1709 (1967)
Microanalysis of the Stable Isotopes of Oxygen by Means of Nuclear Reactions A rapid a n d nondestructive m e t h o d for t h e determina tion of very small quantities of the stable isotopes of oxygen has been ωdeveloped, based on t h e use of t h e nuclear reactions 1 6 Ο ( ρ , « 1) 71 ϊ Ν ; 1 O ( d , a ) l e N ; M 0 ( d , a : ) " N ; 18 0 12 ( d , p ) 1 ! O ; land 0 ( d , p ) 0 . A m o u n t s of t h e order of 10~ gram of s O can be detected. GEORGES AMSEL, Ecole Normale Supérieure, Laboratoire de Physique, Paris, France, and DAVID SAMUEL, Isotope Department, Weizmann Institute of Science, Rehovoth, Israel Anal. Chem. 39, 1689 (1967)
An Improved Spectrophotometric Method the Determination of Sulfate w i t h Barium Chloranilate as Applied t o Coal Ash and Related M a t e r i a l s
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Reported is a study of t h e use of 8 0 % isopropyl alcohol in the determination of sulfate with barium chloranilate, the factors affecting reliability and sensitivity of t h e method, a n d t h e possible interference from chloride, phos phate, and fluoride. H. N. S. SCHAFER, Coal Research Laboratory, CSIRO Division of Mineral Chemistry, P. O. Box 175, Chatswood, N. S. W . , Aus tralia Anal. Chem. 39, 1719 (1967)
Infrared Spectrometric Examination of Paper. I. Techniques and Fiber Composition B y immersing paper sheets in a liquid whose refractive index is about 1.5, the infrared spectra obtained can b e used to measure the groundwood content of paper from the ratio of the aromatic ring a n d / o r carbonyl bands from lignins to t h e aliphatic carbon to hydrogen b a n d of cellulose. CLARA D. SMITH and J O H N K. WISE. United States Gypsum Co., Chicago, 111. Anal. Chem. 39, 1698 (1967)
Rapid Combustion Method f o r the Determination of Sulfur in Nickel-, Iron-, and CopperBase Alloys T h e use of treated vanadium (V) oxide in standard com bustion techniques improves t h e sulfur yield so t h a t 90 ± 10% of t h e sulfur is recovered in a variety of standard samples. T h e precision of t h e m e t h o d on a maraging steel is within 0.0006% a t the 0.0120% level a n d within 0.0005% at t h e 0.005% level on a nickel-base standard. KEITH E. BURKE, Paul D. Merica Research Laboratory, Interna tional Nickel Co., Inc., Sterling Forest, Suffern, Ν. Υ. Ι090Ι Anal. Chem. 39, 1727 (1967)
I n f r a r e d Spectrometric Examination of Paper. I I . Determination of U r e a - F o r m a l d e h y d e Resin T h e reported procedure permitting t h e determination of urea-formaldehyde resin in paper in the range of 0.3 t o 3.0% from infrared spectra obtained directly on t h e paper sample gives most accurate results when carried o u t b y techniques of differential spectrometry on paper specimens m a d e translucent b y an oil coating. J O H N K. WISE and CLARA D. SMITH, United States Gypsum Co., Chicago, III.
Emission Response of Some Hydrocarbon—Methanol Solutions in Hydrogen Flames T h e technique of limited area flame spectrometry (LAFS) is used to study the prominent band-head of the C H emitter at 431.5 ταμ and of d at 516 πιμ. PETER F. McCREA and TRUMAN S. LIGHT, Research Center, The Foxboro Co., 38 Neponset Ave., Foxboro, Mass. 02035 Anal. Chem. 39, 1731 (1967)
Anal. Chem. 39, 1702 (1967)
The Use of an Ion Beam Chopper f o r Improved Precision in Spark Source Mass Spectrography Spectrophotometric Determination of Thorium w i t h Molybdophosphoric Acid T h e m e t h o d reported is sensitive for thorium in t h e range of 0.2 to 1000 μ&. T h e molar absorptivity was calculated to be 3.3 χ 104. Heteropoly acid formation was also in vestigated. BRYAN L. M A D I S O N and J O H N C. G U Y O N , Department of Chemistry, University of Missouri, Columbia, Mo. 65201 Anal. Chem. 39, 1706 (1967) •
