Extraction of dithiocarbamic acids from solutions of their salts

1982 ◽  
Vol 47 (11) ◽  
pp. 2876-2881 ◽  
Author(s):  
Drahomír Oktavec ◽  
Bohumil Síleš ◽  
Ján Remeň ◽  
Václav Konečný ◽  
Ján Garaj
Keyword(s):  
Aqueous Phase ◽  
Time Dependent ◽  
Absorption Bands ◽  
Decomposition Reactions ◽  
Maximum Extraction ◽  
The Stability ◽  
Kinetics Of ◽  
Alkali Salts ◽  
Nm Range

The extraction of dithiocarbamic acids with chloroform from aqueous phase containing their alkali salts has been investigated with regard to the fact that absorbing strongly in the 200-310 nm range, the acids interfere with the spectrophotometric determination of metals whose dithiocarbamate ligands exhibit their analytical absorption bands in that region. The amount of the dithiocarbamic acids formed depends on the kinetics of their formation and decomposition reactions and on the pH of the aqueous phase. The stability of the acids in chloroform extracts is highly time dependent. The maximum extraction of the acids (R2NCS2H) is attained at the following pH (R, pH): CH3 5.0, C2H5 5.9, C3H8 6.3, C4H9 6.8, C5H11 6.9, C6H13 6.9, iso-C3H7 7.2, iso-C4H9 6.9; for (CH3, iso-C3H7)NCS2H 7.3, C5H10NCS2H 7.2, C4H8ONCS2H 5.2.

scholarly journals Phytochemical Molecules from the Decarboxylation of Gomphrenins in Violet Gomphrena globosa L.—Floral Infusions from Functional Food

2020 ◽  
Vol 21 (22) ◽  
pp. 8834
Author(s):  
Natalia Drobnicka ◽  
Katarzyna Sutor ◽  
Agnieszka Kumorkiewicz-Jamro ◽  
Aneta Spórna-Kucab ◽  
Michał Antonik ◽  
...  
Keyword(s):  
Citric Acid ◽  
High Resolution Mass Spectrometry ◽  
Potential Health ◽  
Gomphrena Globosa ◽  
Brewing Process ◽  
Health Promoting ◽  
The Stability ◽  
Kinetics Of ◽  
Derivatives Of

Herein, the generation of decarboxylated derivatives of gomphrenin pigments exhibiting potential health-promoting properties and the kinetics of their extraction during tea brewing from the purple flowers of Gomphrena globosa L. in aqueous and aqueous citric acid solutions were investigated. Time-dependent concentration monitoring of natural gomphrenins and their tentative identification was carried out by LC-DAD-ESI-MS/MS. The high content of acylated gomphrenins and their principal decarboxylation products, 2-, 15-, 17-decarboxy-gomphrenins, along with minor levels of their bidecarboxylated derivatives, were reported in the infusions. The identification was supported by the determination of molecular formulas of the extracted pigments by liquid chromatography coupled with high-resolution mass spectrometry (LCMS-IT-TOF). The influence of plant matrix on gomphrenins’ stability and generation of their derivatives, including the extraction kinetics, was determined by studying the concentration profiles in the primary and diluted infusions. Isolated and purified acylated gomphrenins from the same plant material were used for the preliminary determination of their decarboxylated derivatives. The acylated gomphrenins were found to be more stable than nonacylated ones. Citric acid addition had a degradative influence on natural gomphrenins mainly during the longer tea brewing process (above 15 min); however, the presence of plant matrix significantly increased the stability for betacyanins’ identification.

Transient kinetics of nucleation and crystallization: Part II. Crystallization

1991 ◽  
Vol 6 (10) ◽  
pp. 2097-2102 ◽  
Author(s):  
G. Shi ◽  
J.H. Seinfeld
Keyword(s):  
Experimental Data ◽  
Large Time ◽  
Volume Fraction ◽  
Time Dependent ◽  
Transient Kinetics ◽  
Amorphous Phases ◽  
Time Limits ◽  
The Stability ◽  
Analytical Expressions ◽  
Kinetics Of

Analytical expressions for the time-dependent crystallized volume fraction are derived from new results for the transient rate of nucleation reported in Part I. Conventional formulations that have been used in interpreting crystallization experimental data and for assessing the stability of amorphous phases are shown to be large time limits of the newly derived expressions. An approach for assessing the stability of an amorphous phase is proposed.

scholarly journals Determination of solubility, stability and degradation kinetics of morin hydrate in physiological solutions

RSC Advances ◽  
2018 ◽  
Vol 8 (50) ◽  
pp. 28836-28842 ◽  
Author(s):  
Ashok Kumar Jangid ◽  
Deep Pooja ◽  
Hitesh Kulhari
Keyword(s):  
Degradation Kinetics ◽  
Morin Hydrate ◽  
The Stability ◽  
Kinetics Of

The stability of morin hydrate depends on pH, temperature, and light.

scholarly journals DISTRIBUTION OF THORIUM (IV) IONS IN AQUEOUS EXFOLIATING SYSTEM CONTAINING ANTIPYRINE AND SULFOSALICYLIC ACID

2021 ◽  
Vol 64 (5) ◽  
pp. 19-23
Author(s):  
Mikhail I. Degtev ◽  
Aleksandra A. Yuminova
Keyword(s):  
Aqueous Phase ◽  
Room Temperature ◽  
Photometric Determination ◽  
Sulfosalicylic Acid ◽  
Salting Out ◽  
Maximum Extraction ◽  
Instrumental Methods ◽  
Toxic Organic Solvents ◽  
Nitrate Solutions

The possibilities of an aqueous delaminating system containing antipyrine (AP) and sulfosalicylic acid (SSA) for extracting macro - and microamounts of thorium (IV) were studied. The proposed extraction system eliminates the use of toxic organic solvents. The dependences of the distribution of metal from nitrate solutions between phases on the concentration of reagents, acidity of the medium, the amount of inorganic salting-out agent (NaNO3, NH4NO3, Na2SO4) and the volume of the aqueous phase are determined, and optimal conditions for extraction are found. It is shown that in the organic phase with a volume of 1.6 ml at room temperature, macro-and microamounts of thorium (IV) are extracted by 88 and 90%, respectively. The maximum extraction of the cation is achieved at the ratio of AP: SSA = 2.0 : 1.0 and their concentration, mol/l: 0.6: 0.3, while the acidity of the medium created by nitric acid should be equal to 0.015 mol/l (pHequ. = 1.8-1.9). The extraction of thorium (IV) becomes quantitative if inorganic salts (sodium sulfate, sodium nitrate) are introduced into the AP – SSA – 0,015 mol/l HNO3 – H2O system, which, by reducing the activity of water, increase the concentration of reagents in the aqueous phase. The concentration of salting-out agents should correspond to 1.0 and 2.5 mol/l. A mechanism for the distribution of a mixed thorium (IV) complex containing AP, SSA, nitrate ions, solvated with a salt of antipyrinium sulfosalicylate is proposed. The extract is mixed in any relationship with distilled water, providing the use of various instrumental methods of analysis. A method for extraction-photometric determination of thorium (IV) with a toron indicator has been developed. The limit for the fulfillment of the Bouguer-Lambert-Beer law is established. The apparent coefficient of light absorption is calculated (ε = 1.7∙104).

Determination of the Grain Coarsening Temperature in Nb Microalloyed Steels by Multiphase-Field Model

2016 ◽  
Vol 879 ◽  
pp. 921-925
Author(s):  
Jeong Min Kim ◽  
Sok Yun Hong ◽  
Ji Hun Jang ◽  
Kyung Jong Lee
Keyword(s):  
Field Model ◽  
Volume Fraction ◽  
Mean Field ◽  
Time Dependent ◽  
Microalloyed Steels ◽  
Pinning Force ◽  
Grain Coarsening ◽  
Dimensional Growth ◽  
Kinetics Of

The grain coarsening temperature in Nb microalloyed steels is investigated by multiphase-field model. In this study, the pinning force is treated as time-dependent using mean-field kinetics of precipitates including volume fraction and their size. The grain size is calculated with time under various temperature range. The grain coarsening temperature is determined by the ratio of the largest radius of grain vs. the average grain radius criteria (Rmax / Ravg > 2.94) in two-dimensional growth. Through this model, it is possible to simulate grain growth in microalloyed steels more precisely.

scholarly journals An HPLC and UHPLC-HRMS Approach to Study PSMA-11 Instability in Aqueous Solution

2020 ◽  
Author(s):  
ANTONELLA IUDICELLO ◽  
Filippo Genovese ◽  
Valentina Di Iorio ◽  
Gianfranco Cicoria ◽  
Stefano Boschi
Keyword(s):  
Analytical Method ◽  
Radiochemical Purity ◽  
Time Dependent ◽  
Dependent Manner ◽  
Compound Structure ◽  
High Affinity ◽  
Secondary Compound ◽  
The Stability ◽  
Definition Of

Abstract Background. Stability of precursors and reagents are of utmost importance for developing a suitable, fast and routinely reproducible analytical method for the quality control of radiopharmaceuticals, for the validation of the analytical method itself, as well as for radiolabeling procedure. During the validation of the analytical method used for the determination of chemical and radiochemical purity of an injectable solution of 68Ga-PSMA-11, a trend to instability of the PSMA-11 standard, the same used as a precursor in the radiosynthesis of 68Ga-PSMA11, has been found. This instability led to the formation of a secondary compound in a time-dependent manner. The formation of this compound made difficult the validation of the analytical method and influenced the radiolabeling yield, by increasing free 68Ga which, obviously, decreased the final yield.Results. The nature of this compound was investigated by adding chelators, such as EDTA, to PSMA-11 solutions and by using the combination of UHPLC-HRMS. The results led to the definition of the secondary compound structure, as natFe-PSMA-11, from the combination of the high affinity chelator HBED-CC, present in the molecule of PSMA-11, and environmental Fe(III).Conclusions. Strategies to reduce the risk of low radiolabeling yields and to increase the stability of the standards were also discussed.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

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