نتایج جستجو برای: nonaqueous acid

تعداد نتایج: 748562  

2006
Cevdet DEMİR Yasin YÜCEL

Mixture experimental design was used to enhance the separation selectivity of metal ions in nonaqueous capillary electrophoresis. The separation of cations (Ag, Fe, Cr, Mn, Cd, Co, Pb, Ni, Zn and Cu) was achieved using imidazole as UV co-ion for indirect detection. Acetic acid was chosen as an electrolyte because its cathodic electroosmotic flow permits faster separation. The composition of org...

Journal: :Journal of chromatography. A 2010
Hsiu-Li Su Wan-Chun Kao Cheng-Yu Lee Shih-Ching Chuang You-Zung Hsieh

In this study, nonaqueous capillary electrophoresis (NACE) was used to separate three open-cage fullerenes. Trifluoroacetic acid (TFA) was used as the nonaqueous background electrolyte to change the analytes' mobilities. The selectivity and separation efficiency were critically affected by the nature of the buffer system, the choice of organic solvent, and the concentrations of TFA and sodium a...

1997
Lech Chmurzynski

The ultraviolet spectra of heterocyclic N-oxides of pyridine N-oxide series and the conjugated cationic acids (simple cations of protonated N-oxides) in acetonitrile as the representative of polar aprotic solvents, were determined. The obtained spectra of N-oxides studied (mainly tri-substituted pyridine N-oxides) and their cations obtained by the protonation of free N-oxides by the excess of p...

2008
R. D. Falcone

Aqueous and nonaqueous AOT/n-heptane reverse micelles where characterized by UV-Visible and fluorescence spectroscopy of AO. The study shows the presence of the dimer in aqueous reverse micelles which is not present in the nonaqueous systems. It seems that there is a conversion of the dimer to monomer in the aqueous reverse micelles at high AOT concentration. In the nonaqueous systems, there is...

2013
Zheng Han Youxiang Zuo

A two parameters equation of state (EOS) for nonaqueous electrolyte solutions system has been developed. The equation is in terms of Helmholtz free energy and incorporated with results of low density expansion of non-primitive mean spherical approximation. The EOS was tested for experimental data reported in literatures of 9 nonaqueous single electrolyte solutions of which the temperature was 2...

Journal: :Physical chemistry chemical physics : PCCP 2015
Ryota Jono Yoshitaka Tateyama Koichi Yamashita

We demonstrate the redox potential calculation relative to the normal hydrogen electrode (NHE) in nonaqueous solution using a density functional theory-based molecular dynamics (DFT-MD) simulation. The calculation of the NHE in nonaqueous solution consists of two processes: the first step is the equilibrated simulation for a proton in nonaqueous solution to determine the space for inserting a p...

2014
Elliot J. Lawrence Vasily S. Oganesyan David L. Hughes Andrew E. Ashley Gregory G. Wildgoose

Frustrated Lewis pairs have found many applications in the heterolytic activation of H2 and subsequent hydrogenation of small molecules through delivery of the resulting proton and hydride equivalents. Herein, we describe how H2 can be preactivated using classical frustrated Lewis pair chemistry and combined with in situ nonaqueous electrochemical oxidation of the resulting borohydride. Our app...

Journal: :Journal of AOAC International 2004
Sheikha M Al-Ghannam Abdalla Abulkibash Abeer M Al-Olyyan

The application of direct-current differential electrolytic potentiometry to the nonaqueous titration of amino acids was investigated. The basic character of amino acids in acetic acid was enhanced to permit their direct titration with perchloric acid. A pair of antimony electrodes was used as an indicating system. The shapes of the titration curves obtained were almost symmetrical with sharp p...

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