scholarly journals Determination of the main spectral characteristics and conditions for the extraction of the cationic dye pyronine G with higher carboxylic acids

2020 ◽  
Vol 64 (12) ◽  
pp. 83-87
Author(s):  
Viachaslau U. Zhylko ◽  
◽  
Natalia V. Nekhan ◽  
Keyword(s):  
Carboxylic Acids ◽  
Polar Phase ◽  
Cationic Dye ◽  
Alkaline Ph ◽  
Photometric Analysis ◽  
Extinction Coefficients ◽  
Ph Values ◽  
Selection Of ◽  
Molar Extinction Coefficients

The selection of the suitable cationic dye is one of the key steps in extraction-photometric methods for the quantitative determination of hydrophobic anions, in particular, higher carboxylic acids. No less important is the reasonable selection of the required polar phase pH for extraction systems. It is because higher carboxylic acids are well extracted by non-polar phase in molecular form. It was found that, in contrast to other cationic dyes, pyronine G, which is stable in high alkaline pH values, is well extracted in form of ionic associates with higher carboxylic acids. The optimal composition of organic phase (5% solution by volume of n-octanol-1 in heptane) was found for quantitative analysis of higher carboxylic acids in the form of associates with pyronine G, at which the blank sample has a rather low optical density. Molar extinction coefficient of dyes for quantitative photometric analysis is an equally important characteristic of their optical properties. These properties depend on not only the nature of the substance itself, but also on the solvent. The molar extinction coefficients for organic (5.3·104 l·mol-1·cm-1) and aqueous phases (3.6·104 l·mol-1·cm-1) were determined for the above-found optimal extraction system for pyronine G with palmitic acid (water – 5% solution by volume of n-octanol-1 in heptane). They are 1.5-2 times higher than the molar extinction coefficients of safranin T and other cationic dyes used in the photometric analysis of hydrophobic acids in high alkaline pH values. Thus, the cationic dye pyronine G use for quantitative extraction-photometric analysis of higher carboxylic acids seems to be very promising.

scholarly journals Spectrophotometric Determination of the Ionization Constants for the Oximes – Cholinesterases Reactivators at Different Temperatures

2019 ◽  
Vol 2 (3) ◽  
pp. e00097
Author(s):  
T.V. Schäfer ◽  
A.A. Tyaptin ◽  
T.B. Pechurina
Keyword(s):  
Aqueous Solutions ◽  
Incubation Medium ◽  
Ph Value ◽  
Ionization Constants ◽  
Medium Ph ◽  
Extinction Coefficients ◽  
Spectrophotometric Data ◽  
Different Temperatures ◽  
Molar Extinction Coefficients

The goal of study was the determination of the ionization constants for the oximes – cholinesterases reactivators in aqueous solutions at different temperatures. The wavelengths of absorption maxima of the protonated and deprotonated oxime groups, the molar extinction coefficients of the various oximes species, and the ionization constants for the oxime cholinesterases reactivators (isonitrosin, pralidoxime, dipyroxime, toxogonin, methoxime, carboxime and asoxime) were obtained using spectrophotometric data (wavelength 190 to 450 nm) in solutions (pH 5 – 12) at 20°C, 25°C and 37°C. The proportion of nucleophilic forms involved in the oxime-induced reactivation of phosphorylated cholinesterases was shown to be is positively dependent on the incubation medium pH value and temperature. A hypothesis that the temperature affects the oximes ability to reactivate phosphorylated cholinesterases has been proposed.

scholarly journals Molar extinction coefficient of fullerenes and related hydrogenated derivatives “fulleranes”

2011 ◽  
Vol 7 (S283) ◽  
pp. 324-325 ◽  
Author(s):  
Franco Cataldo ◽  
Susana Iglesias-Groth ◽  
Arturo Manchado
Keyword(s):  
Infrared Spectra ◽  
Molar Absorptivity ◽  
Laboratory Scale ◽  
Extinction Coefficients ◽  
Protoplanetary Nebulae ◽  
Astrophysical Objects ◽  
Carbon Molecules ◽  
Derivatives Of ◽  
Molar Extinction Coefficients

AbstractFullerenes, the carbon molecules with 60 and 70 atoms, were recently detected in a series of planetary nebulae, in protoplanetary nebulae and in other astrophysical objects. The detection and the quantitative determination of these molecules was made possible by the measurement of their reference infrared spectra and the relative molar extinction coefficients and integrated molar absorptivity on laboratory scale. It is expected that also fulleranes the hydrogenated derivatives of C60 and C70 may be present in the same objects where fullerenes were detected. This prompted us to synthesize the hydrogenated fullerenes, to record their infrared spectra and the measure the molar extinction coefficients and integrated molar absorptivity on laboratory scale to have a reference in the search of these fullerene derivatives in space

Determination of the molar extinction coefficients of the deuteroferriheme analogs of peroxidase enzyme compounds I and II

1992 ◽  
Vol 31 (7) ◽  
pp. 1144-1147 ◽  
Author(s):  
Fanny S. Woo ◽  
Ricardo E. Rodriguez ◽  
Dale A. Huckaby ◽  
Peter Jones ◽  
Henry C. Kelly
Keyword(s):  
Extinction Coefficients ◽  
Peroxidase Enzyme ◽  
Molar Extinction Coefficients

Photochromism of peri-aryloxy-p-quinones. Determination of molar extinction coefficients of 6-phenoxy-5,11-naphthacenequinones

1979 ◽  
Vol 30 (5) ◽  
pp. 691-693
Author(s):  
Yu. E. Gerasimenko ◽  
A. A. Parshutkin ◽  
N. T. Poteleshchenko ◽  
V. P. Poteleshchenko ◽  
V. V. Romanov
Keyword(s):  
Extinction Coefficients ◽  
Molar Extinction Coefficients

Determination of molar extinction coefficients for endohedral metallofullerene Dy@C82(C2v)

2016 ◽  
Vol 65 (10) ◽  
pp. 2421-2424
Author(s):  
I. E. Kareev ◽  
V. M. Nekrasov ◽  
A. E. Dutlov ◽  
V. P. Bubnov ◽  
V. M. Martynenko ◽  
...  
Keyword(s):  
Extinction Coefficients ◽  
Endohedral Metallofullerene ◽  
Molar Extinction Coefficients

scholarly journals Using photocaging for fast time-resolved structural biology studies

2021 ◽  
Vol 77 (10) ◽  
pp. 1218-1232
Author(s):  
Diana C. F. Monteiro ◽  
Emmanuel Amoah ◽  
Cromarte Rogers ◽  
Arwen R. Pearson
Keyword(s):  
Structural Biology ◽  
Spectroscopic Properties ◽  
Decay Rates ◽  
Quantum Yields ◽  
Fast Time ◽  
Time Resolved ◽  
Extinction Coefficients ◽  
Reaction Initiation ◽  
Selection Of ◽  
Molar Extinction Coefficients

Careful selection of photocaging approaches is critical to achieve fast and well synchronized reaction initiation and perform successful time-resolved structural biology experiments. This review summarizes the best characterized and most relevant photocaging groups previously described in the literature. It also provides a walkthrough of the essential factors to consider in designing a suitable photocaged molecule to address specific biological questions, focusing on photocaging groups with well characterized spectroscopic properties. The relationships between decay rates (k in s−1), quantum yields (φ) and molar extinction coefficients (ɛmax in M −1 cm−1) are highlighted for different groups. The effects of the nature of the photocaged group on these properties is also discussed. Four main photocaging scaffolds are presented in detail, o-nitrobenzyls, p-hydroxyphenyls, coumarinyls and nitrodibenzofuranyls, along with three examples of the use of this technology. Furthermore, a subset of specialty photocages are highlighted: photoacids, molecular photoswitches and metal-containing photocages. These extend the range of photocaging approaches by, for example, controlling pH or generating conformationally locked molecules.

Sign in / Sign up

Export Citation Format

Share Document