Photodegradation kinetics of lisdexamfetamine dimesylate and structure elucidation of its degradation products by LC-ESI-QTOF

2018 ◽  
Vol 10 (19) ◽  
pp. 2287-2292 ◽  
Author(s):  
Graciela Carlos ◽  
Jéferson Segalin ◽  
Louise Jank ◽  
Eloisa Comiran ◽  
Marcella Herbstrith de Oliveira ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Structure Elucidation ◽  
Degradation Products ◽  
Lisdexamfetamine Dimesylate ◽  
Kinetics Of

Herein, we investigate the photodegradation of lisdexamfetamine (LDX) in an aqueous solution.

Photodegradation kinetics of lodenafil carbonate, structure elucidation of two major degradation products using UPLC-MS/MS and in vitro cytotoxicity

2013 ◽  
Vol 5 (22) ◽  
pp. 6511 ◽  
Author(s):  
Cristiane Franco Codevilla ◽  
Alini Dall Cortivo Lange ◽  
Juliana Maria de Mello Andrade ◽  
Jéferson Segalin ◽  
Pedro Eduardo Fröehlich ◽  
...  
Keyword(s):  
Structure Elucidation ◽  
Degradation Products ◽  
In Vitro Cytotoxicity ◽  
Kinetics Of

Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics And Mechanism ◽  
Kinetic Constants ◽  
Steric Factors ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

scholarly journals Conformation Transition Kinetics of Silk Fibroin in Aqueous Solution Explored Using Circular Dichroism Spectroscopy

2021 ◽  
Vol 6 (8) ◽  
pp. 1735-1740
Author(s):  
Sora Lee ◽  
Soo Hyun Kim ◽  
You‐Young Jo ◽  
Wan‐Taek Ju ◽  
Hyun‐Bok Kim ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Circular Dichroism ◽  
Silk Fibroin ◽  
Circular Dichroism Spectroscopy ◽  
Kinetics Of ◽  
Circular Dichroïsm ◽  
Conformation Transition

scholarly journals Degradation Kinetics of Humic acid in Aqueous Solution by Ozonation Treatment under Different Parameter Conditions

2020 ◽  
Vol 596 ◽  
pp. 012010
Author(s):  
Zafirah Mahyun ◽  
Noor Fazliani Shoparwe ◽  
Ahmad Zuhairi Abdullah ◽  
Abdul Latif Ahmad ◽  
Mardawani Mohamad ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Degradation Kinetics ◽  
Kinetics Of

scholarly journals Leaching Titaniferous Magnetite Concentrate by Alkaline Aqueous Solution

2021 ◽  
Author(s):  
Ke Guo ◽  
Shaoyan Wang ◽  
Renfeng Song ◽  
Zhiqiang Zhang
Keyword(s):  
Aqueous Solution ◽  
Alkali Concentration ◽  
Water Usage ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Iron Concentrate ◽  
Titaniferous Magnetite ◽  
Magnetite Concentrate ◽  
Kinetics Of

AbstractLeaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

scholarly journals Characterization and Study on Fragmentation Pathways of a Novel Nerve Agent, ‘Novichok (A234)’, in Aqueous Solution by Liquid Chromatography–Tandem Mass Spectrometry

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1059
Author(s):  
Jin Young Lee ◽  
Kyoung Chan Lim ◽  
Hyun Suk Kim
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Degradation Products ◽  
Aqueous Sample ◽  
Tandem Mass ◽  
Aqueous Samples ◽  
Fragmentation Pathways ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

As a first step toward studying the properties of Novichok (ethyl (1-(diethylamino)ethylidene)phosphoramidofluoridate (A234)), we investigated its degradation products and fragmentation pathways in aqueous solution at different pH levels by liquid chromatography–tandem mass spectrometry. A234 was synthesized in our laboratory and characterized by nuclear magnetic resonance spectroscopy. Three sets of aqueous samples were prepared at different pH levels. A stock solution of A234 was prepared in acetonitrile at a concentration of 1 mg/mL and stored at −20 °C until use. Aqueous samples (0.1 mg/mL) were prepared by diluting the stock solution with deionized water. The acidic aqueous sample (pH = 3.5) and basic aqueous sample (pH = 9.4) were prepared using 0.01 M acetic acid and 0.01 M potassium carbonate, respectively. The analysis of the fragmentation patterns and degradation pathways of A234 showed that the same degradation products were formed at all pH levels. However, the hydrolysis rate of A234 was fastest under acidic conditions. In all three conditions, the fragmentation pattern and the major degradation product of A234 were determined. This information will be applicable to studies regarding the decontamination of Novichok and the trace analysis of its degradation products in various environmental matrices.

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