Results 251 to 260 of about 383,654 (289)
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Quantitative 1H-NMR analysis of amniotic fluid
Journal of Pharmaceutical and Biomedical Analysis, 1993Ten amniotic fluid samples (36-38 weeks gestation) are analysed by NMR spectroscopy. Of the species identified in the spectra, valine (mean 198 microM: SEM 57 microM), lactate (9.73 mM; 2.05 mM), alanine (689 microM: 115 microM), acetate (6.87 mM: 1.54 mM), citrate (363 microM: 59 microM), glucose (4.54 mM: 1.28 mM) indoxyl-sulphate (n = 4,270 microM),
P E, McGowan +5 more
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1H and13C NMR analysis of some trichothecenes
Archives of Environmental Contamination and Toxicology, 19891H and 13C NMR chemical shifts were determined from the NMR spectra of low concentration solutions of T-2 toxin, T-2 triol, HT-2 toxin, diacetoxyscirpenol, and neosolaniol. Isomerization of neosolaniol was observed to occur in chloroform solution. 1D and 2D 1H and 13C NMR techniques were used in order to determine the structure of the isomerization ...
M, Mesilaakso, M, Moilanen, E, Rahkamaa
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Analysis of membrane lipids by 500 MHz 1H NMR
Analytical Biochemistry, 1989A nondestructive method has been developed for rapid analysis of lipid content of membrane extracts based on high field proton NMR spectroscopy. Lipid extraction is done by stepwise sonication of purified membranes into chloroform:methanol:water mixtures, and 1H spectra are recorded at 35 degrees C on final preparations consisting of at least 1 mg ...
M L, Sparling +3 more
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Quantitative analysis of hydrogen peroxide by 1H NMR spectroscopy
Analytical and Bioanalytical Chemistry, 2005A technique utilizing 1H NMR spectroscopy has been developed to measure the concentration of hydrogen peroxide from 10(-3) to 10 M. Hydrogen peroxide produces a peak at around 10-11 ppm, depending upon the interaction between solvent molecules and hydrogen peroxide molecules.
Ned A, Stephenson, Alexis T, Bell
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Journal of Pharmaceutical and Biomedical Analysis, 2008
Counterfeit and/or imitation medicines are becoming a major health problem not only in developing countries but also in wealthier countries. The need of new and easy analytical methods for quality control of drugs is essential. We describe the use of Raman spectroscopy, 1H nuclear magnetic resonance (NMR) and 2D diffusion-ordered spectroscopy (DOSY ...
Saleh, Trefi +5 more
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Counterfeit and/or imitation medicines are becoming a major health problem not only in developing countries but also in wealthier countries. The need of new and easy analytical methods for quality control of drugs is essential. We describe the use of Raman spectroscopy, 1H nuclear magnetic resonance (NMR) and 2D diffusion-ordered spectroscopy (DOSY ...
Saleh, Trefi +5 more
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1H NMR peptide sequential analysis using superconducting magnets
Journal of Magnetic Resonance (1969), 1974Abstract The principle, scope, and limitations of methods for sequence determination of oligopeptides by variation of pH with and without addition of lanthanide salt shift reagents (LsR) are discussed. Although the latter method seems very promising for aqueous solutions in general, extensive line broadening in alkaline medium poses serious ...
Marc Anteunis, R Callens
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1H NMR analysis of sporopollenin from Typha Angustifolia
Phytochemistry, 1999Abstract The first analysis of sporopollenin using 1H NMR-techniques revealed the presence of four phenolic compounds in different amounts. The phenolic compounds are tri- or tetrasubstituted. The sporopollenin was isolated and purified from Typha angustifolia by an enzymatic procedure, followed by extraction with organic solvents.
Friedhelm Ahlers +4 more
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