scholarly journals HYDROPHOBIC AROMATIC THIO (DITIO) COMPOUNDS AS CHROMOGENIC ANALYTICAL REAGENTS FOR PHOTOMETRIC DETERMINATION OF THIOLS BY MERCAPTO GROUP. I. CHROMOGENIC DISULFIDES I. II. STABILITY OF ANALYTICAL EFFECTS

2020 ◽  
Vol 53 ◽  
pp. 51-56
Author(s):  
Kirill V. Veksler ◽  
◽  
Evgenia N. Volkova ◽  
Aleksander G. Goncharenko ◽  
◽  
...  
Keyword(s):  
Photometric Determination ◽  
Mercapto Group ◽  
Group I ◽  
Analytical Reagents

scholarly journals HYDROPHOBIC AROMATIC THIO (DITHIO)COMPOUNDS AS CHROMOGENIC ANALYTICAL REAGENTS FOR PHOTOMETRIC DETERMINATION OF THIOLS BY MERCAPTO GROUP II. A UNIFIED MOLECULAR MODEL OF THE ANALYTICAL REAGENT

2020 ◽  
Vol 55 ◽  
pp. 49-57
Author(s):  
Kirill V. Veksler ◽  
◽  
Evgenia N. Volkova ◽  
Alexander G. Gontсharenko ◽  
◽  
...  
Keyword(s):  
Reaction Center ◽  
Molecular Model ◽  
Spectral Characteristics ◽  
Photometric Determination ◽  
Azo Compounds ◽  
Substitution Reactions ◽  
Mercapto Group ◽  
Sh Reagents ◽  
Analytical Reagents ◽  
Analytical Reagent

The concept of a unified molecular model is proposed for the directed synthesis of chromogenic analytical reagents for the mercapto group in ("thiol-thiol") substitution reactions (SH reagents). The unified molecular model of the SH reagent includes an aromatic chromophore-containing thio fragment covalently bound by an ordinary bond on a sulfide sulfur atom to an electrophilic, relatively soft one [in terms of the principle of hard and soft acids and bases (the HSAB principle)] reaction center. The characteristics of the analytical effect of the SH reagent are determined by the structure of the thio fragment. The required change in the reactivity and selectivity of the SH reagent are achieved mainly by varying the softness (stiffness) of the reaction center. Spectral characteristics of analytical effects, reactivity and selectivity of SH reagents (obtained earlier and synthesized for the first time in this work) – hydrophobic aromatic thio (dithio) compounds: thiocyanates, symmetric disulfides, and thiomercuric compounds – were studied in an aprotic dipolar DMF medium. In support of the concept of the unified molecular model for compounds containing identical thiofragments it was established: - spectral characteristics of the analytical effect of all three types of compounds (thiocyanates, disulfides and thiomercuric compounds) are the same in the DMF medium. - in accordance with the principle of HSAB, the reactivity increases in the sequence thiocyanate < disulfide <<thiomercuric compound, which corresponds to an increase in the softness of the reaction center in the series: -С << - S-<< -Hg-. The universality of the concept of the unified molecular model follows from consideration of the spectral and kinetic characteristics not only of Ellman reagent, but as well of thio(dithio)azo compounds, thiocyanate and thiomercuric compound containing the same 3-carboxy, 4-nitrophenylthio fragment.

Photometric determination of copper (II) microquantities in pyrite

2019 ◽  
Vol 85 (10) ◽  
pp. 23-28
Author(s):  
F. S. Aliyeva ◽  
F. O. Mamedova ◽  
F. N. Bahmanova ◽  
Yu. A. Yusibov ◽  
F. M. Chyragov
Keyword(s):  
Photometric Determination ◽  
Determination Of Copper

Spectrophotometric study of the reactions of lanthanoids with bromopyrogallol red in the presence of cation active tensides

1982 ◽  
Vol 47 (2) ◽  
pp. 503-508 ◽  
Author(s):  
Irena Němcová ◽  
Pavla Plocková ◽  
Tran Hong Con
Keyword(s):  
Absorption Spectra ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Optimal Conditions ◽  
Bromopyrogallol Red ◽  
Binary Complexes

The absorption spectra of the binary complexes of lanthanoids with bromopyrogallol red were measured and the formation of ternary complexes with cation active tenside, Septonex, was studied. Optimal conditions were found for the formation of these complexes and the possibility of their use in the photometric determination of lanthanoids was demonstrated on several examples.

scholarly journals Evolution of Antennapedia-Class Homeobox Genes

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 295-303 ◽  
Author(s):  
Jianzhi Zhang ◽  
Masatoshi Nei
Keyword(s):  
Gene Expression ◽  
Homeobox Genes ◽  
Amino Acid Sequences ◽  
Gene Arrangement ◽  
Gene Duplications ◽  
Group I ◽  
Group 3 ◽  
Group Ii ◽  
Anterior Posterior

Antennapedia (Antp)-class homeobox genes are involved in the determination of pattern formation along the anterior-posterior axis of the animal embryo. A phylogenetic analysis of Antp-class homeodomains of the nematode, Drosophila, amphioxus, mouse, and human indicates that the 13 cognate group genes of this gene family can be divided into two major groups, i.e., groups I and II. Group I genes can further be divided into subgroups A (cognate groups 1–2), B (cognate group 3), and C (cognate groups 4–8), and group II genes can be divided into subgroups D (cognate groups 9–10) and E (cognate groups 11–13), though this classification is somewhat ambiguous. Evolutionary distances among different amino acid sequences suggest that the divergence between group I and group II genes occurred ∼1000 million years (MY) ago, and the five different subgroups were formed by ∼600 MY ago, probably before the divergence of Pseudocoelomates (e.g., nematodes) and Coelomates (e.g., insects and chordates). Our results show that the genes that are phylogenetically close are also closely located in the chromosome, suggesting that the colinearity between the gene expression and gene arrangement was generated by successive tandem gene duplications and that the gene arrangement has been maintained by some sort of selection.

ChemInform Abstract: FLAME PHOTOMETRIC DETERMINATION OF POTASSIUM IN TUNGSTEN

1978 ◽  
Vol 9 (38) ◽  
Author(s):  
H.-J. LUNK ◽  
G. HENRION ◽  
D. MARQUARDT ◽  
TR. JENTZSCH
Keyword(s):  
Photometric Determination

scholarly journals PHOTOMETRIC DETERMINATION OF ARGININE

1942 ◽  
Vol 145 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Erwin Brand ◽  
Beatrice Kassell
Keyword(s):  
Photometric Determination
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