Determination of the temperature profile during telemetric probing of the atmosphere within the ??5 mm oxygen (O2) absorption band

1981 ◽  
Vol 24 (3) ◽  
pp. 210-213
Author(s):  
N. N. Markina ◽  
M. I. Sumin
Keyword(s):  
Absorption Band ◽  
Temperature Profile

scholarly journals Determination of effective axial temperature profile in tube furnaces via the Viscous Stretching Method

2015 ◽  
Vol 5 (9) ◽  
pp. 2024
Author(s):  
Zhiwen Pan ◽  
Jens Kobelke ◽  
Kay Schuster ◽  
Hartmut Bartelt
Keyword(s):  
Temperature Profile ◽  
Axial Temperature ◽  
Tube Furnaces

DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules

1980 ◽  
Vol 63 (5) ◽  
pp. 1049-1051
Author(s):  
Juan A Squella ◽  
Luis J Nunez-Vergara ◽  
Maximo Aros
Keyword(s):  
Absorption Band ◽  
Spectrophotometric Determination ◽  
Degradation Product ◽  
Uv Absorption ◽  
Acidic Hydrolysis ◽  
Average Recovery ◽  
Polarographic Wave ◽  
Spectrophotometric Methods ◽  
Hydrolysis Of

Abstract Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively

Determination of hydroxyl concentrations in prepolymers from the infrared absorption band of tetrahydrofuran-associated hydroxyl groups

1982 ◽  
Vol 54 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Chung Sul Youn. Kim ◽  
Allan L. Dodge ◽  
Suk Fai. Lau ◽  
Andrew. Kawasaki
Keyword(s):  
Absorption Band ◽  
Infrared Absorption ◽  
Hydroxyl Groups ◽  
Infrared Absorption Band

Recent Advances in the Chemistry of Covalently Bound Flavin Coenzymes

1972 ◽  
Vol 27 (9) ◽  
pp. 1069-1071 ◽  
Author(s):  
W. C. Kenney ◽  
W. H. Walker ◽  
E. B. Kearney ◽  
R. Seng ◽  
T. P. Singer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Absorption Band ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Hypsochromic Shift ◽  
Ninhydrin Reaction ◽  
Acid Environment ◽  
Definite Proof ◽  
Covalently Bound

Following elucidation of the structures of the flavin components of succinate dehydrogenase (SD) as N (3) -histidyl-8α-FAD and of monoamine oxidase (MAO) as cysteinyl-8α-FAD and determination of the peptide sequences around the flavin sites of these enzymes, attention has been focused on the covalently bound FAD of Chromatium cytochrome c-552. As documented in preliminary communications, the FAD moiety of this enzyme is also substituted at the 8α-position, as judged from ESR hyderfine structure of the free radical cation and the characteristic hypsochromic shift of the second absorption band of the neutral flavoquinone in purified preparations of the flavin. Definite proof has come from the liberation of 8-carbxyriboflavin on performic acid treatment of the enzyme. In regard to ESR and optical spectra and the tendency of the purified flavin (liberated by proteolysis) to undergo autooxidation with a further hypsochromic shift of the second absorption band and increased fluorescence, the flavin resembles the MAO flavin. The fact that fluorescence is >90% quenched at all pH values even at the FMN level and doees not vary with pH between 3.2 and 8 also suggests a thioether linkage as in cysteinyl riboflavin. In many respects, however, the Chromatium flavin differs from cysteinyl riboflavin. Highly purified preparations from tryptic-chymotryptic digests give a positive chloroplatinic test. Electrophoresis clearly shows the presence of carboxyl and amino groups but the peptide gives no characteristic ninhydrin reaction and amino acid analysis of performic acid oxidized samples yields cysteic acid and threonine in amounts less than equimolar to the flavin. The amino acid environment around the flavin may account for these results although a linkage other than a thioether remains a possibility.

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