BRIEFS The Determination of dl- and mesoDibromosuccinic Acids in Aqueous Solutions The acid concentration is determined polarographically and compared to the amount remaining after 60 minutes in NaOH at 25° C. Since only the dl isomer reacts quan titatively during this interval, the final limiting current can be related directly to the original concentration of the meso isomer. RAYMOND A N N I N O and DAVID J . MANZO, Department of Chemistry, Canisius College, Buffalo, Ν. Υ. Anal. Chem. 36, 1343 (1964)
Microdetermination of Polyoxyethylene and Polyoxypropylene Surface Active Agents
ΗANOVIA high-intensity mercury vapor arc lamps for photochemistry
After pyrolysis in th3 presence of phosphoric acid, the acetaldehyde produced from the polyoxyethylene type of compounds and the propionaldehyde produced from the polyoxypropylene type were detected by Rosen's reagent, and the resulting colored complexes were measured at 565 ταμ and 405 ταμ, respectively. JOSEPH LEE WILLIAMS and HORACE G R A H A M , George Wash ington Carver Foundation, Tuskegee Institute, A l a .
Hanovia's experience in ultraviolet and quartz products over the past 50 years is responsible for a com plete line of high-intensity mercury vapor arc lamps and accessories for photochemical work on an experi mental or commercial basis. Ultraviolet radiation and near-visi ble violet and blue have already in duced a great many photo-reactions, including halogenations, oxidations, hydrogénations, polymerizations, isomerizations, nitrogen and iron reduction, and decompositions. All have been induced without hazard to personnel or damage to equipment, thanks to a completely automatic system of protective devices developed by Hanovia. Photochemical systems by Hanovia include sturdily-built immersion wells, lamps and accessories, and have been designed to fit readily with standard laboratory apparatus. The following is a partial list of lamps that are fully tested and available:
Anal. Chem. 36, 1345 (1964)
An Infrared Study of the C = N Stretching Vibration in Azine Derivatives of Aldehydes and Ketones The C:=N stretching vibration in azines is found to lie in the region 1610 to 1665 cm. -1 , with an intensity of from one third to one half that of the carbonyl absorption in the parent compound. LEO D. FREDERICKSON, Jr., Spectran Laboratories, Inc., Denver, Coio. Anal. Chem. 36, 1349 (1964)
Spectrofluorometric Phenothiazines
Measurement
of
In studying 31 phenothiazines and three thioxanthenes, it was found that oxidation with hydrogen peroxide and heat prior to analysis yield more stable solutions and greatly increase fluorescence. All compounds examined could be measured in submicrogram quantities. JAMES B. RAGLAND and V. J O H N KINROSS-WRIGHT, Houston State Psychiatric Institute and Baylor University College of Medi cine, Houston, Tex. Anal. Chem. 36, 1356 (1964)
Determination of Submicrogram Amounts of Selenium in Biological Materials The analysis is completed by measuring the Se concen tration fluorometrically after reaction with 2,3-diaminonaphthalene. Agreement with neutron activation analy ses, recovery of added selenite, and standard deviations are within ±0.02 μg. of Se. W . H. ALLAWAY and EARLE E. CARY, Agricultural Research Service, U. S. Department of Agriculture, Ithaca, Ν. Υ. Anal. Chem. 36, 1359 (1964)
Analytical Applications Long-Tube Vaporizers
and Construction
Volts
Watts
608A 654A 679A 673A 674A 1B9A
90-110 115-130 125-140 140-150 _J150__ 285
100 200 450 550 700 1200
1.2 Γ ,1.9 £o 3.7 % ΕΓ 4.5 [ " 71 12.0 0
550
2000
21.0
1 = 3°
47A
925
3450
48.0
J » -o
59A 77A 57A 40B
1000 960 1260 1700
4500 4500 5000 7500
58.0 £ = . 42.0 s " 46.5 [ ™ 59.0
78A
For further information on complete systems for photochemical reactions of all types, write today.
of
Arc Length In.
Lamp Model
ENGELHARD HANOVIA. INC.
The apparatus described gives reproducible residue de terminations on heat-sensitive mixtures. Rapid phase separation helps minimize polymerization and thermal decomposition. B. D. ASH, Research and Development Department, Union Carbide Chemicals Division, South Charleston, W . Va.
ΗANOVIA L A M P
D I V I S I O N
100 CHESTNUT STREET · NEWARK 5, NEW JERSEY
Anal. Chem. 36, 1363 (1964)
131
Circle No. 51 on Readers' Service Carl
VOL. 36 NO. 7 JUNE 1964 ·
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