The Experts below are selected from a list of 14175 Experts worldwide ranked by ideXlab platform
Linxiao Gao - One of the best experts on this subject based on the ideXlab platform.
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spectrophotometric determinatIon of tiopronin using its catalytic reactIon between sodium 1 2 naphthoquinone 4 sulfonate and Hydroxyl Ion
Analytical Sciences, 2009Co-Authors: Linxiao GaoAbstract:A novel and simple spectrophotometric method for the determinatIon of tiopronin with sodium 1,2-naphthoquinone-4-sulfonate (NQS) is established in this paper. The detailed mechanism is proposed and discussed. It is based on the fact that tiopronin can catalyze the reactIon between sodium 1,2-naphthoquinone-4-sulfonate and Hydroxyl Ion to form 2-hydroxy-1,4-naphthoquinone in a buffer solutIon of pH 13.00 at the maximal absorptIon wavelength of 445 nm. When tetradecyl benzyl dimethyl ammonium chloride (Zeph) is added to the solutIon, the sensitivity of the reactIon is improved. Beer's law is obeyed in a range of 0.39 - 15.67 microg mL(-1). The equatIon of linear regressIon is A = 0.11749 + 0.05914C (microg mL(-1)), with a linear correlatIon coefficient of 0.9973. The detectIon limit is 0.2 microg mL(-1), RSD is 0.88% and the recovery rate is in the range of 96.6 - 103.9%. Furthermore, the method has been validated and successfully applied to the determinatIon of tiopronin in pharmaceutical samples.
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Catalysis reactIon between sodium 1,2-naphthoquinone-4-sulfonate and Hydroxyl Ion using captopril as catalyzer and determinatIon of captopril.
Analytica chimica acta, 2008Co-Authors: Linxiao GaoAbstract:Abstract A novel and simple spectrophotometric method for the determinatIon of Captopril with sodium 1,2-naphthoquinone-4-sulfonate is established in this paper. The detailed reactIon mechanism is proposed and discussed. It is based on the fact that captopril can catalyze the reactIon between sodium 1,2-naphthoquinone-4-sulfonate and Hydroxyl Ion to form 2-hydroxy-1,4-naphthoquinone in buffer solutIon of pH 13.00. Beer's law is obeyed in a range of 0.64–80 μg mL−1 at the maximal absorptIon wavelength of 442 nm. The equatIon of linear regressIon is A = 0.05815 + 0.00589C (μg mL−1), with a linear regressIon correlatIon coefficient of 0.9981. The detectIon limit is 0.3 μg mL−1, R.S.D. is 0.77% and the recovery rate is in range of 96.0–103.8%. Furthermore, the method has been validated and successfully applied to the determinatIon of captopril in pharmaceutical samples.
Ivan S. Ufimtsev - One of the best experts on this subject based on the ideXlab platform.
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a multistate empirical valence bond model for solvatIon and transport simulatIons of oh in aqueous solutIons
Physical Chemistry Chemical Physics, 2009Co-Authors: Ivan S. Ufimtsev, Andrey G. Kalinichev, Todd J. Martínez, James R KirkpatrickAbstract:We describe a new multistate empirical valence bond (MS-EVB) model of OH− in aqueous solutIons. This model is based on the recently proposed “charged ring” parameterizatIon for the intermolecular interactIon of Hydroxyl Ion with water [Ufimtsev, et al., Chem. Phys. Lett., 2007, 442, 128] and is suitable for classical molecular simulatIons of OH− solvatIon and transport. The model reproduces the hydratIon structure of OH−(aq) in good agreement with experimental data and the results of ab initio molecular dynamics simulatIons. It also accurately captures the major structural, energetic, and dynamic aspects of the proton transfer processes involving OH− (aq). The model predicts an approximately two-fold increase of the OH− mobility due to proton exchange reactIons.
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A multistate empirical valence bond model for solvatIon and transport simulatIons of OH− in aqueous solutIons
Physical Chemistry Chemical Physics, 2009Co-Authors: Ivan S. Ufimtsev, Andrey G. Kalinichev, Todd J. Martínez, R. James KirkpatrickAbstract:We describe a new multistate empirical valence bond (MS-EVB) model of OH− in aqueous solutIons. This model is based on the recently proposed “charged ring” parameterizatIon for the intermolecular interactIon of Hydroxyl Ion with water [Ufimtsev, et al., Chem. Phys. Lett., 2007, 442, 128] and is suitable for classical molecular simulatIons of OH− solvatIon and transport. The model reproduces the hydratIon structure of OH−(aq) in good agreement with experimental data and the results of ab initio molecular dynamics simulatIons. It also accurately captures the major structural, energetic, and dynamic aspects of the proton transfer processes involving OH− (aq). The model predicts an approximately two-fold increase of the OH− mobility due to proton exchange reactIons.
Gunnar Karlström - One of the best experts on this subject based on the ideXlab platform.
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Study of the Hydroxyl Ion in water. A combined quantum chemical and statistical mechanical treatment.
The Journal of Physical Chemistry A, 2003Co-Authors: Jose M. Hermida-ramón, Gunnar KarlströmAbstract:A combined quantum mechanical-statistical mechanical method has been used to study the behavior of the Hydroxyl Ion in water. The system is divided into three parts, a quantum core (the Ion), 89 classical water molecules, and a dielectric continuum. The water molecules are represented using a polarizable potential. The first solvatIon shell consists of four water molecules, two linked by hydrogen bonds to the oxygen of the Ion and the other two linked to the hydrogen of the Ion. The intermolecular distances obtained are in the same range as those in previous calculatIons. The intramolecular bond length in the Ion decreases by 0.09 au upon solvatIon relative to the gas-phase value.
Huanhuan Zhang - One of the best experts on this subject based on the ideXlab platform.
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Study of methanol catalyzed reactIon between sodium 1,2-naphthoquine-4-sulfonate and Hydroxyl Ion and its applicatIon in the determinatIon of methanol.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2007Co-Authors: Huanhuan ZhangAbstract:Abstract A novel and simple spectrophotometric method for the direct determinatIon of methanol with 1,2-naphthoquinone-4-sulfonate (NQS) is developed in this paper. It is based on the fact that methanol can catalyze the reactIon between 1,2-naphthoquinone-4-sulfonate and Hydroxyl Ion to form 2-hydroxy-1,4-naphthoquinone in buffer solutIon of pH 13.00. Beer's law is obeyed in a range of 0.26–15.8 mg/ml at the maximal absorptIon wavelength of 454 nm. The equatIon of linear regressIon is A = 0.01998 + 0.05944 C (mg/ml), with a linear regressIon correlatIon coefficient of 0.9977. The detectIon limit is 0.25 mg/ml (3 σ / k ), while R.S.D. is 2.0% and the recovery rate is in a range of 96.5–103%. The detailed mechanism for the formatIon of the products is proposed and discussed.
R. James Kirkpatrick - One of the best experts on this subject based on the ideXlab platform.
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A multistate empirical valence bond model for solvatIon and transport simulatIons of OH− in aqueous solutIons
Physical Chemistry Chemical Physics, 2009Co-Authors: Ivan S. Ufimtsev, Andrey G. Kalinichev, Todd J. Martínez, R. James KirkpatrickAbstract:We describe a new multistate empirical valence bond (MS-EVB) model of OH− in aqueous solutIons. This model is based on the recently proposed “charged ring” parameterizatIon for the intermolecular interactIon of Hydroxyl Ion with water [Ufimtsev, et al., Chem. Phys. Lett., 2007, 442, 128] and is suitable for classical molecular simulatIons of OH− solvatIon and transport. The model reproduces the hydratIon structure of OH−(aq) in good agreement with experimental data and the results of ab initio molecular dynamics simulatIons. It also accurately captures the major structural, energetic, and dynamic aspects of the proton transfer processes involving OH− (aq). The model predicts an approximately two-fold increase of the OH− mobility due to proton exchange reactIons.
