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Sample records for 1h nmr uv-vis

  1. UV/vis, 1H, and 13C NMR spectroscopic studies to determine mangiferin pKa values.

    PubMed

    Gómez-Zaleta, Berenice; Ramírez-Silva, María Teresa; Gutiérrez, Atilano; González-Vergara, Enrique; Güizado-Rodríguez, Marisol; Rojas-Hernández, Alberto

    2006-07-01

    The acid constants of mangiferin (a natural xanthonoid) in aqueous solution were determined through an UV/vis spectroscopic study employing the SQUAD program as a computational tool. A NMR study complements the pK(a) values assignment and evidences a H-bridge presence on 1-C. The chemical model used was consistent with the experimental data obtained. The pK(a) values determined with this procedure were as follows: H(4)(MGF)=H(3)(MGF)(-)+H(+), pKa1 (6-H)=6.52+/-0.06; H(3)(MGF)(-)=H(2)(MGF)(2-)+H(+), pKa2 (3-H)=7.97+/-0.06; H(2)(MGF)(2-)=H(MGF)(3-)+H(+), pKa3 (7-H)=9.44+/-0.04; H(MGF)(3-)=(MGF)(4-)+H(+), pKa4 (1-H)=12.10+/-0.01; where it has been considered mangiferin C(19)H(18)O(11) as H(4)(MGF). Mangiferin UV/vis spectral behavior, stability study in aqueous solution as well as NMR spectroscopy studies: one-dimensional (1)H,(13)C, 2D correlated (1)H/(13)C performed by (g)-HSQC and (g)-HMBC methods; are also presented. pK(a) values determination of H(4)(MGF) in aqueous solution is a necessary contribution to subsequent pharmacokinetic study, and a step towards the understanding of its biological effects.

  2. Experimental (FT-IR, FT-Raman, UV-Vis, 1H and 13C NMR) and computational (density functional theory) studies on 3-bromophenylboronic acid

    NASA Astrophysics Data System (ADS)

    Karabacak, M.; Kose, E.; Atac, A.; Sas, E. B.; Asiri, A. M.; Kurt, M.

    2014-11-01

    Structurally, boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent (i.e., C-Br bond) and two hydroxyl groups to fill the remaining valences on the boron atom. We studied 3-bromophenylboronic acid (3BrPBA); a derivative of boronic acid. This study includes the experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV-Vis) techniques and theoretical (DFT-density functional theory) calculations. The experimental data are recorded, FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase. 1H and 13C NMR spectra are recorded in DMSO solution. UV-Vis spectrum is recorded in the range of 200-400 nm for each solution (in ethanol and water). The theoretical calculations are computed DFT/B3LYP/6-311++G(d,p) basis set. The optimum geometry is also obtained from inside for possible four conformers using according to position of hydrogen atoms after the scan coordinate of these structures. The fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and parallel quantum solutions (PQS) program. 1H and 13C NMR chemical shifts are racked on by using the gauge-invariant atomic orbital (GIAO) method. The time-dependent density functional theory (TD-DFT) is used to find HOMO and LUMO energies, excitation energies, oscillator strengths. The density of state of the studied molecule is investigated as total and partial density of state (TDOS and PDOS) and overlap population density of state (OPDOS or COOP) diagrams have been presented. Besides, frontier molecular orbitals (FMOs), molecular electrostatic potential surface (MEPs) and thermodynamic properties are performed. At the end of this work, the results are ensured beneficial for the literature contribution.

  3. Combined experimental and theoretical studies on the X-ray crystal structure, FT-IR, 1H NMR, 13C NMR, UV-Vis spectra, NLO behavior and antimicrobial activity of 2-hydroxyacetophenone benzoylhydrazone.

    PubMed

    Sheikhshoaie, Iran; Ebrahimipour, S Yousef; Sheikhshoaie, Mahdeyeh; Rudbari, Hadi Amiri; Khaleghi, Moj; Bruno, Giuseppe

    2014-04-24

    A Schiff base ligand, 2-hydroxyacetophenone benzoylhydrazone (HL) was synthesized and fully characterized with FT-IR, elemental analyses, UV-Vis, (1)H NMR and (13)C NMR spectra. DFT calculations using B3LYP/6-31+G(d,p) and PW91/DZP are performed to optimize the molecular geometry. Optimized structures are used to calculate FT-IR, UV-Vis, (1)H NMR and (13)C NMR spectra of the compound. Also the energies of the frontier molecular orbitals (FMOs) have been determined. The results obtained from the optimization and spectral analyses are in good agreement with the experimental data. To investigate non-linear optical properties, the electric dipole moment (μ), polarizability (α) and molecular first hyperpolarizability (β) were computed. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the compound can be a good candidate of nonlinear optical materials. In addition, the minimal inhibitory concentration (MIC) of this compound against Staphylococcus aureus, and Candida albicans was determined.

  4. Theoretical and spectroscopic (FT-IR, NMR and UV-Vis.) characterizations of 3-p-chlorobenzyl-4-(4-carboxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-one molecule

    NASA Astrophysics Data System (ADS)

    Akyıldırım, Onur; Gökce, Halil; Bahçeli, Semiha; Yüksek, Haydar

    2017-01-01

    Fourier transform infrared (FT-IR) spectroscopy in the region 400-4000 cm-1, proton and carbon-13 NMR chemical shifts and UV-Vis. absorption wavelengths of 3-p-chlorobenzyl-4-(4-carboxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-one molecule have been experimentally investigated. For monomeric and dimeric forms of the title molecule, the optimized molecular structure analyses, vibrational wavenumbers, 13C and 1H NMR chemical shifts and electronic absorption wavelengths of the title molecule have been performed at DFT/B3LYP method with 6-311G(d,p) basis set. The HOMO and LUMO analyses have been theoretically done by using the mentioned calculation level. The obtained experimental values have been compared with calculated data. The computed vibrational frequencies, NMR chemical shifts and UV-Vis. wavelengths have been found to be in a good agreement with experimental values and spectral results of similar structures in the literature.

  5. FT-IR, UV-vis, 1H and 13C NMR spectra and the equilibrium structure of organic dye molecule disperse red 1 acrylate: a combined experimental and theoretical analysis.

    PubMed

    Cinar, Mehmet; Coruh, Ali; Karabacak, Mehmet

    2011-12-01

    This study reports the characterization of disperse red 1 acrylate compound by spectral techniques and quantum chemical calculations. The spectroscopic properties were analyzed by FT-IR, UV-vis, (1)H NMR and (13)C NMR techniques. FT-IR spectrum in solid state was recorded in the region 4000-400 cm(-1). The UV-vis absorption spectrum of the compound that dissolved in methanol was recorded in the range of 200-800 nm. The (1)H and (13)C NMR spectra were recorded in CDCl(3) solution. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR spectrum. A satisfactory consistency between the experimental and theoretical spectra was obtained and it shows that the hybrid DFT method is very useful in predicting accurate vibrational structure, especially for high-frequency region. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. A study on the electronic properties were performed by timedependent DFT (TD-DFT) and CIS(D) approach. To investigate non linear optical properties, the electric dipole moment μ, polarizability α, anisotropy of polarizability Δα and molecular first hyperpolarizability β were computed. The linear polarizabilities and first hyperpolarizabilities of the studied molecule indicate that the compound can be a good candidate of nonlinear optical materials.

  6. UV-vis, IR and 1H NMR spectroscopic studies of some mono- and bis-azo-compounds based on 2,7-dihydroxynaphthalene and aniline derivatives

    NASA Astrophysics Data System (ADS)

    Issa, Raafat M.; Fayed, Tarek A.; Awad, Mohammed K.; El-Kony, Sanaa M.

    2005-12-01

    The absorption spectra of mono- and bis-azo-derivatives obtained by coupling the diazonium salts of aromatic amines and 2,7-dihydroxynaphthalene have been studied in six organic solvents. The different absorption bands have been assigned and the effect of solvents on the charge transfer band is also discussed. The diagnostic IR spectral bands and 1H NMR signals are assigned and discussed in relation to molecular structure. Also, semi-empirical molecular orbital calculations using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory have been performed to investigate the molecular and electronic structures of these compounds. According to these calculations, an intramolecular hydrogen bonding is essential for stabilization of such molecules.

  7. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid

    NASA Astrophysics Data System (ADS)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.

    2014-03-01

    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  8. Monitoring changes in the structure and properties of humic substances following ozonation using UV-Vis, FTIR and (1)H NMR techniques.

    PubMed

    Rodríguez, Francisco J; Schlenger, Patrick; García-Valverde, María

    2016-01-15

    The main objective of this work is to conduct a comprehensive structural characterization of humic substances using the following experimental techniques: FTIR, 1H NMR and several UV–Vis parameters (Specific UV Absorbance at 254 nm or SUVA254, SUVA280, A400, the absorbance ratios A210/254, A250/365, A254/203, A254/436, A265/465, A270/400, A280/350, A465/665, the Absorbance Slope Index (ASI), the spectral slopes S275–295, S350–400 and the slope ratio SR). These UV–Vis parameters have also been correlated with key properties of humic substances such as aromaticity, molecular weight (MW) and trihalomethane formation potential (THMFP). An additional objective of this work is also to evaluate the usefulness of these techniques to monitor structural changes in humic substances produced by the ozonation treatment. Four humic substances were studied in this work: three of them were provided by the International Humic Substances Society (Suwannee River Fulvic Acid Standard: SRFA, Suwannee River Humic Acid Standard: SRHA and Nordic Reservoir Fulvic Acid Reference: NLFA) and the other one was a terrestrial humic acid widely used as a surrogate for aquatic humic substances in various studies (Aldrich Humic Acid: AHA). The UV–Vis parameters showing the best correlations with aromaticity in this study were SUVA254, SUVA280, A280/A350 ratio and A250/A364 ratio. The best correlations with molecular weight were for SUVA254, SUVA280 and A280/A350 ratio. Finally, in the case of the THMFP it was STHMFP-per mol HS the parameter showing good correlations with most of the UV–Vis parameters studied (especially with A280/A350 ratio, A265/A465 ratio and A270/A400 ratio) whereas STHMFP-per mg C showed poor correlations in most cases. On the whole, the UV–Vis parameter showing the best results was A280/A350 ratio as it showed excellent correlations for the three properties studied (aromaticity, MW and THMFP). A decrease in aromaticity following ozonation of humic substances can

  9. Quantum mechanical and spectroscopic (FT-IR, FT-Raman,1H,13C NMR, UV-Vis) studies, NBO, NLO, HOMO, LUMO and Fukui function analysis of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione by DFT studies

    NASA Astrophysics Data System (ADS)

    Pandey, Manju; Muthu, S.; Nanje Gowda, N. M.

    2017-02-01

    Theoretical analysis of the molecular structure, spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV-Vis) studies, and thermodynamic characteristics of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione (5MBIT) molecule were done by DFT/B3LYP using 6-311++G(d, p) basis set. Theoretical parameters were compared with experimental data. The dipole moment (μ), polarizability (Δα) and first order hyperpolarizability (β) of the molecule were calculated. Thermodynamic properties, HOMO and LUMO energies were determined. Global reactivity parameters and Fukui function of the 5MBIT molecule were predicted.

  10. Spectroscopic (vibrational, NMR and UV-vis.) and quantum chemical investigations on 4-hexyloxy-3-methoxybenzaldehyde.

    PubMed

    Abbas, Ashgar; Gökce, Halil; Bahçeli, Semiha

    2016-01-05

    In this study, the 4-hexyloxy-3-methoxybenzaldehyde compound as one of the derivatives of vanillin which is a well known flavoring agent, C14H20O3, has been investigated by experimentally and extensively utilizing density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. In this context, the optimized geometry, vibrational frequencies, (1)H and (13)C NMR chemical shifts, UV-vis. (in gas phase and in methanol solvent) spectra, HOMO-LUMO analysis, molecular electrostatic potential (MEP), thermodynamic parameters and atomic charges of 4-hexyloxy-3-methoxybenzaldehyde have been calculated. In addition, theoretically predicted IR, Raman and UV-vis. (in gas phase and in methanol solvent) spectra of the mentioned molecule have been constructed. The results calculated were compared with the experimental data.

  11. Spectroscopic (vibrational, NMR and UV-vis.) and quantum chemical investigations on 4-hexyloxy-3-methoxybenzaldehyde

    NASA Astrophysics Data System (ADS)

    Abbas, Ashgar; Gökce, Halil; Bahçeli, Semiha

    2016-01-01

    In this study, the 4-hexyloxy-3-methoxybenzaldehyde compound as one of the derivatives of vanillin which is a well known flavoring agent, C14H20O3, has been investigated by experimentally and extensively utilizing density functional theory (DFT) at the B3LYP/6-311++G(d,p) level. In this context, the optimized geometry, vibrational frequencies, 1H and 13C NMR chemical shifts, UV-vis. (in gas phase and in methanol solvent) spectra, HOMO-LUMO analysis, molecular electrostatic potential (MEP), thermodynamic parameters and atomic charges of 4-hexyloxy-3-methoxybenzaldehyde have been calculated. In addition, theoretically predicted IR, Raman and UV-vis. (in gas phase and in methanol solvent) spectra of the mentioned molecule have been constructed. The results calculated were compared with the experimental data.

  12. Vibrational (FT-IR and FT-Raman), electronic (UV-Vis), NMR (1H and 13C) spectra and reactivity analyses of 4,5-dimethyl-o-phenylenediamine

    NASA Astrophysics Data System (ADS)

    Atac, Ahmet; Karaca, Caglar; Gunnaz, Salih; Karabacak, Mehmet

    2014-09-01

    The structure of 4,5-dimethyl-o-phenylenediamine (C8H12N2, DMPDA) was investigated on the basis of spectroscopic data and theoretical calculations. The sterochemical structure was determined by FT-IR, FT-Raman, UV, 1H and 13C NMR spectra. An experimental study and a theoretical analysis were associated by using the B3LYP method with Gaussian09 package program. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm-1 and 4000-10 cm-1, respectively. The vibrational spectra were calculated by DFT method and the fundamental vibrations were assigned on the basis of the total energy distribution (TED), calculated with scaled quantum mechanics (SQM) method with Parallel Quantum Solutions (PQS) program. The UV absorption spectrum of the compound that dissolved in ethanol solution were recorded in the range of 190-400 nm. Total density of state (TDOS) and partial density of state (PDOS) of the DMPDA in terms of HOMOs and LUMOs were calculated and analyzed. Chemical shifts were reported in ppm relative to tetramethylsilane (TMS) for 1H and 13C NMR spectra. The compound was dissolved in dimethyl sulfoxide (DMSO). Also, 1H and 13C chemical shifts calculated using the gauge independent atomic orbital (GIAO) method. Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of B3LYP (DFT) method using 6-311++G** basis set. On the basis of the thermodynamic properties of the title compound at different temperatures have been carried out, revealing the correlations between heat capacity (C), entropy (S), enthalpy changes (H) and temperatures. The optimized bond lengths, bond angles, chemical shifts and vibrational wavenumbers showed the best agreement with the experimental results.

  13. Vibrational (FT-IR and FT-Raman), electronic (UV-Vis), NMR (1H and 13C) spectra and reactivity analyses of 4,5-dimethyl-o-phenylenediamine.

    PubMed

    Atac, Ahmet; Karaca, Caglar; Gunnaz, Salih; Karabacak, Mehmet

    2014-09-15

    The structure of 4,5-dimethyl-o-phenylenediamine (C8H12N2, DMPDA) was investigated on the basis of spectroscopic data and theoretical calculations. The sterochemical structure was determined by FT-IR, FT-Raman, UV, 1H and 13C NMR spectra. An experimental study and a theoretical analysis were associated by using the B3LYP method with Gaussian09 package program. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm(-1) and 4000-10 cm(-1), respectively. The vibrational spectra were calculated by DFT method and the fundamental vibrations were assigned on the basis of the total energy distribution (TED), calculated with scaled quantum mechanics (SQM) method with Parallel Quantum Solutions (PQS) program. The UV absorption spectrum of the compound that dissolved in ethanol solution were recorded in the range of 190-400 nm. Total density of state (TDOS) and partial density of state (PDOS) of the DMPDA in terms of HOMOs and LUMOs were calculated and analyzed. Chemical shifts were reported in ppm relative to tetramethylsilane (TMS) for 1H and 13C NMR spectra. The compound was dissolved in dimethyl sulfoxide (DMSO). Also, 1H and 13C chemical shifts calculated using the gauge independent atomic orbital (GIAO) method. Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of B3LYP (DFT) method using 6-311++G** basis set. On the basis of the thermodynamic properties of the title compound at different temperatures have been carried out, revealing the correlations between heat capacity (C), entropy (S), enthalpy changes (H) and temperatures. The optimized bond lengths, bond angles, chemical shifts and vibrational wavenumbers showed the best agreement with the experimental results.

  14. Perylene bisimide dimer aggregates: fundamental insights into self-assembly by NMR and UV/Vis spectroscopy.

    PubMed

    Shao, Changzhun; Grüne, Matthias; Stolte, Matthias; Würthner, Frank

    2012-10-22

    A novel perylene bisimide (PBI) dye bearing one solubilizing dialkoxybenzyl and one bulky 2,5-di-tert-butylphenyl substituent was synthesized and its aggregation behavior was analyzed by NMR and UV/Vis spectroscopy in various chloroform/methylcyclohexane (MCH) solvent mixtures. In the presence of no less than 10 vol % chloroform, exclusive self-assembly of this PBI dye into π-stacked dimers was unambiguously confirmed by means of both concentration-dependent (1) H NMR and UV/Vis spectroscopic experiments. Based on ROESY NMR, a well-defined π-stacked dimer structure was determined and further corroborated by molecular modeling studies. By varying the solvent composition of chloroform and MCH, the solvent effects on the Gibbs free energy of PBI dimerization were elucidated and showed a pronounced nonlinearity between lower and higher MCH contents. This observation could be related to a further growth process of dimers into larger aggregates that occurs in the absence of chloroform, which is required to solvate the aromatic π surfaces. With the help of a single-crystal structure analysis for a related PBI dye, a structural model could be derived for the extended aggregates that are still composed of defined π-π-stacked PBI dimer entities.

  15. Synthesis, crystal structure analysis, spectral (NMR, FT-IR, FT-Raman and UV-Vis) investigations, molecular docking studies, antimicrobial studies and quantum chemical calculations of a novel 4-chloro-8-methoxyquinoline-2(1H)-one: An effective antimicrobial agent and an inhibition of DNA gyrase and lanosterol-14α-demethylase enzymes

    NASA Astrophysics Data System (ADS)

    Murugavel, S.; Sundramoorthy, S.; Lakshmanan, D.; Subashini, R.; Pavan Kumar, P.

    2017-03-01

    The novel title compound 4-chloro-8-methoxyquinoline-2(1H)-one (4CMOQ) has been synthesized by slow evaporation solution growth technique at room temperature. The synthesized 4CMOQ molecule was characterized experimentally by FT-IR, FT-Raman, UV-Vis, NMR and single crystal diffraction (XRD) and theoretically by quantum chemical calculations. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311++G (d,p) basis set in ground state and compared with the experimental data. The entire vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED) by VEDA 4 programme. The nuclear magnetic resonance spectra (1H and 13C NMR) are obtained by using the gauge-invariant atomic orbital (GIAO) method. The change in electron density (ED) in the antibonding orbital's and stabilization energies E(2) of the molecule have been evaluated by natural bond orbital (NBO) analysis to give clear evidence of stabilization. Moreover, electronic characteristics such as HOMO and LUMO energies, Mulliken atomic charges and molecular electrostatic potential surface are investigated. Absorption spectrum analysis, nonlinear optical properties, chemical reactivity descriptors and thermodynamic features are also outlined theoretically. Molecular docking studies were executed to understand the inhibitory activity of 4CMOQ against DNA gyrase and Lanosterol 14 α-demethylase. The antimicrobial activity of 4CMOQ was determined against bacterial strains such as Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and fungal strains such as Aspergillus niger, Monascus purpureus and Penicillium citrinum. The obtained results show that the compound exhibited good to moderate antimicrobial activity.

  16. DFT calculations and experimental FT-IR, FT-Raman, NMR, UV-Vis spectral studies of 3-fluorophenylboronic acid.

    PubMed

    Karabacak, M; Kose, E; Sas, E B; Kurt, M; Asiri, A M; Atac, A

    2015-02-05

    The spectroscopic (FT-IR, FT-Raman, (1)H and (13)C NMR, UV-Vis), structural, electronic and thermodynamical properties of 3-fluorophenylboronic acid (C6H4FB(OH)2), 3FPBA) were submitted by using both experimental techniques and theoretical methods (quantum chemical calculations) in this work. The experimental infrared and Raman spectra were obtained in the region 4000-400 cm(-1) and 3500-10 cm(-1), respectively. The equilibrium geometry and vibrational spectra were calculated by using DFT (B3LYP) with 6-311++G(d,p) basis set. The vibrational wavenumbers were also corrected with scale factor to take better results for the calculated data. The total energy distributions (TED) of the vibrational modes were performed for the assignments of the title molecule by using scaled quantum mechanics (SQM) method. The NMR chemical shifts ((1)H and (13)C) were recorded in DMSO solution. The (1)H and (13)C NMR spectra were computed by using the gauge-invariant atomic orbital (GIAO) method, showing a good agreement with the experimental ones. The last one UV-Vis absorption spectra were analyzed in two solvents (ethanol and water), saved in the range of 200-400 nm. In addition these, HOMO and LUMO energies, the excitation energies, density of states (DOS) diagrams, thermodynamical properties and molecular electrostatic potential surface (MEPs) were presented. Nonlinear optical (NLO) properties and thermodynamic features were performed. The experimental results are combined with the theoretical calculations using DFT calculations to fortification of the paper. At the end of this work, the results were proved our paper had been indispensable for the literature backing.

  17. Impurity profiling of carbocisteine by HPLC-CAD, qNMR and UV/vis spectroscopy.

    PubMed

    Wahl, Oliver; Holzgrabe, Ulrike

    2014-07-01

    For the impurity profiling of the mucolytic and anti-inflammatory drug carbocisteine a high performance liquid chromatographic (HPLC) method using corona charged aerosol detection (CAD) was developed and fully validated following the ICH guideline Q2(R1). The response was linear (R²>0.995) over a small concentration range (0.05-0.25 or 0.10-0.60% respectively) and a detection limit of at least 0.03% was registered. The separation was achieved on a mixed mode column combining hydrophobic C18 and strong cation exchange retention mechanisms using a mass spectrometer compatible volatile mobile phase consisting of trifluoroacetic acid 10 mM and acetonitrile 12% (V/V). Impurities, not assessable by HPLC-CAD such as the volatile chloroacetic acid and the unstable cysteine, were determined by quantitative NMR (qNMR) with maleic acid as internal standard and UV/vis spectroscopy after reaction with Ellman's reagent, respectively. Six batches of three different manufacturers were tested by means of those methods. The purity varied from below 99.0 to higher than 99.8 per cent. The major impurities of all batches were the starting material cystine and N,S-dicarboxymethylcysteine being a synthesis by-product.

  18. Spectral analysis, vibrational assignments, NBO analysis, NMR, UV-Vis, hyperpolarizability analysis of 2-aminofluorene by density functional theory.

    PubMed

    Jone Pradeepa, S; Sundaraganesan, N

    2014-05-05

    In this present investigation, the collective experimental and theoretical study on molecular structure, vibrational analysis and NBO analysis has been reported for 2-aminofluorene. FT-IR spectrum was recorded in the range 4000-400 cm(-1). FT-Raman spectrum was recorded in the range 4000-50 cm(-1). The molecular geometry, vibrational spectra, and natural bond orbital analysis (NBO) were calculated for 2-aminofluorene using Density Functional Theory (DFT) based on B3LYP/6-31G(d,p) model chemistry. (13)C and (1)H NMR chemical shifts of 2-aminofluorene were calculated using GIAO method. The computed vibrational and NMR spectra were compared with the experimental results. The total energy distribution (TED) was derived to deepen the understanding of different modes of vibrations contributed by respective wavenumber. The experimental UV-Vis spectra was recorded in the region of 400-200 nm and correlated with simulated spectra by suitably solvated B3LYP/6-31G(d,p) model. The HOMO-LUMO energies were measured with time dependent DFT approach. The nonlinearity of the title compound was confirmed by hyperpolarizabilty examination. Using theoretical calculation Molecular Electrostatic Potential (MEP) was investigated.

  19. Reaction pathways of proton transfer in hydrogen-bonded phenol-carboxylate complexes explored by combined UV-vis and NMR spectroscopy.

    PubMed

    Koeppe, Benjamin; Tolstoy, Peter M; Limbach, Hans-Heinrich

    2011-05-25

    Combined low-temperature NMR/UV-vis spectroscopy (UVNMR), where optical and NMR spectra are measured in the NMR spectrometer under the same conditions, has been set up and applied to the study of H-bonded anions A··H··X(-) (AH = 1-(13)C-2-chloro-4-nitrophenol, X(-) = 15 carboxylic acid anions, 5 phenolates, Cl(-), Br(-), I(-), and BF(4)(-)). In this series, H is shifted from A to X, modeling the proton-transfer pathway. The (1)H and (13)C chemical shifts and the H/D isotope effects on the latter provide information about averaged H-bond geometries. At the same time, red shifts of the π-π* UV-vis absorption bands are observed which correlate with the averaged H-bond geometries. However, on the UV-vis time scale, different tautomeric states and solvent configurations are in slow exchange. The combined data sets indicate that the proton transfer starts with a H-bond compression and a displacement of the proton toward the H-bond center, involving single-well configurations A-H···X(-). In the strong H-bond regime, coexisting tautomers A··H···X(-) and A(-)···H··X are observed by UV. Their geometries and statistical weights change continuously when the basicity of X(-) is increased. Finally, again a series of single-well structures of the type A(-)···H-X is observed. Interestingly, the UV-vis absorption bands are broadened inhomogeneously because of a distribution of H-bond geometries arising from different solvent configurations.

  20. Combined experimental and quantum chemical studies on spectroscopic (FT-IR, FT-Raman, UV-Vis, and NMR) and structural characteristics of quinoline-5-carboxaldehyde

    NASA Astrophysics Data System (ADS)

    Kumru, Mustafa; Altun, Ahmet; Kocademir, Mustafa; Küçük, Vesile; Bardakçı, Tayyibe; Şaşmaz, İbrahim

    2016-12-01

    Comparative experimental and theoretical studies have been performed on the structure and spectral (FT-IR, FT-Raman, UV-Vis and NMR) features of quinoline-5-carboxaldehyde. Quantum chemical calculations have been carried out at Hartree-Fock and density functional B3LYP levels with the triple-zeta 6-311++G** basis set. Two stable conformers of quinoline-5-carboxaldehyde arising from the orientation of the carboxaldehyde moiety have been located at the room temperature. The energetic separation of these conformers is as small as 2.5 kcal/mol with a low transition barrier (around 9 kcal/mol). Therefore, these conformers are expected to coexist at the room temperature. Several molecular characteristics of quinoline-5-carboxaldehyde obtained through B3LYP and time-dependent B3LYP calculations, such as conformational stability, key geometry parameters, vibrational frequencies, IR and Raman intensities, UV-Vis vertical excitation energies and the corresponding oscillator strengths have been analyzed. The 1H and 13C NMR chemical shifts of quinoline-5-carboxaldehyde were also investigated.

  1. Conformational analysis, UV-VIS, MESP, NLO and NMR studies of 6-methoxy-1,2,3,4-tetrahydronaphthalene.

    PubMed

    Arivazhagan, M; Kavitha, R; Subhasini, V P

    2014-07-15

    The detailed HF and B3LYP/6-311++G(d,p) comparative studies on the complete FT-IR and FT-Raman spectra of 6-methoxy-1,2,3,4-tetrahydronaphthalene [MTHN] have been studied. In view of the special properties and uses, the present investigation has been undertaken to provide a satisfactorily vibrational analysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene. Therefore, a thorough Raman, IR, molecular electrostatic potential (MESP), non-linear optical (NLO) properties, UV-VIS, HOMO-LUMO and NMR spectroscopic investigation are reported complemented by B3LYP theoretical predictions with basis set 6-311++G(d,p) to provide novel insight on vibrational assignments and conformational stability of MTHN. Potential energy surface scans (PES) of the CH3 group are undertaken to shed light on the rather complicated conformational interchanges in the compound under investigation.

  2. Structural and spectroscopic (UV-Vis, IR, Raman, and NMR) characteristics of anisaldehydes that are flavoring food additives: A density functional study in comparison with experiments

    NASA Astrophysics Data System (ADS)

    Altun, Ahmet; Swesi, O. A. A.; Alhatab, B. S. S.

    2017-01-01

    The molecular structures, vibrational spectra (IR and Raman), electronic spectra (UV-Vis and DOS), and NMR spectra (13C and 1H) of p-anisaldehyde, m-anisaldehyde, and o-anisaldehyde have been studied by using the B3LYP density functional and the 6-311++G** basis set. While p-anisaldehyde has been found to contain two stable conformers at room temperature, m-anisaldehyde and o-anisaldehyde contain four stable conformers. In agreement with the calculated ground-state energetics and small transition barriers, the comparison of the experimental and calculated spectra of the anisaldehydes indicates equilibrium between all conformers at room temperature. However, the two conformers of o-anisaldehyde, in which the methoxy group lies out of the ring plane, are too rare at the equilibrium. The equilibrium conditions of the conformers of the anisaldehyde isomers have been shown readily accessible through UV-Vis and 13C NMR spectral studies but requiring very detailed vibrational analyses. The effect of the solvent has been found to red-shift the electronic absorption bands and to make the anisaldehydes more reactive and soft. Molecular electrostatic potential maps of the anisaldehydes show that their oxygen atoms are the sites for nucleophilic reactivity. Compared with the most sophisticated NBO method, ESP charges have been found mostly reliable while Mulliken charges fail badly with the present large 6-311++G** basis set. The present calculations reproduce not only the experimental spectral characteristics of the anisaldehydes but also reveal their several structural features.

  3. Solute-solvent interactions of acid-1,4-dioxane mixtures-By dielectric, FTIR, UV-vis and 13C NMR spectrometric methods.

    PubMed

    Arivazhagan, G; Parthipan, G; Thenappan, T

    2009-11-01

    Results of the dielectric studies carried out on the binary mixture of n-butyric and caprylic acids with 1,4-dioxane over the entire composition range and at temperatures 303K, 308K, 313K and 318K, and FTIR, UV-vis and 13C NMR spectral studies are presented in this paper. The excess permittivity and excess free energy were fitted with the Redlich-Kister polynomial. The variation of Kirkwood correlation factors, excess permittivity and excess free energy of mixing with the concentration and temperature has been investigated in view of understanding the ordering of dipoles of solute and solvent molecules. The FTIR, UV-vis and 13C NMR spectral analysis reveals the formation of complex between solute and solvent molecules. The parallel alignment of electric dipoles of the complex predicted by dielectric studies is well supported by UV-vis spectral analysis. The structure of the complex molecule present in the clusters has been deduced.

  4. Characterization of fractionated asphaltenes by UV-vis and NMR self-diffusion spectroscopy.

    PubMed

    Ostlund, Jenny-Ann; Wattana, Piyarat; Nydén, Magnus; Fogler, H Scott

    2004-03-15

    Asphaltenes have been fractionated by liquid/liquid extraction, yielding four subfractions. The characteristics of fractionated asphaltenes were studied with respect to solubility, aromaticity, heteroatom content, and diffusion behavior. It was observed that asphaltenes from the four subfractions showed variations in their tendency to flocculate and also distinct differences in aromaticity. Furthermore, NMR self-diffusion studies showed that the average diffusion coefficients varied for asphaltenes from the different subfractions. The results suggest a variation in average size and stability between asphaltenes, depending on what subfraction they belong to. The subfraction that consisted of asphaltenes with the largest average size and the highest aromaticity was also found to contain the asphaltenes that had the strongest tendency to flocculate.

  5. Spectroscopic (FT-IR, FT-Raman, FT-NMR and UV-Vis) investigation on benzil dioxime using quantum computational methods

    NASA Astrophysics Data System (ADS)

    Bakkiyaraj, D.; Periandy, S.; Xavier, S.

    2016-03-01

    The spectral analysis of benzil dioxime is carried out using the FTIR, FT Raman, FT NMR and UV-Vis spectra of the compound with the help of quantum computations by density functional theories. The FT-IR (4000 - 400 cm-1) and FT-Raman (4000-100 cm-1) spectra are recorded in solid phase, the 1H and 13C NMR spectra in DMSO phase and the UV spectrum (200-400 nm) in ethanol phase. The different conformers of the compound and their minimum energies are studied by potential energy surface scan, using semi-empirical method PM6. The computed wavenumbers from different methods are scaled so as to agree with the experimental values and the scaling factors are reported. All the fundamental modes have been assigned based on the potential energy distribution (PED) values and the structure the molecule is analyzed interms of parameters like bond length, bond angle and dihedral angles predicted byB3LYP and CAM-B3LYP methods with cc-pVDZ basis sets. The values of dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the molecule are reported, using which the non -linear optical property of the molecule is discussed. The HOMO-LUMO mappings are reported which reveals the different charge transfer possibilities within the molecule. The isotropic chemical shifts predicted for 1H and 13C atoms using gauge invariant atomic orbital (GIAO) theory show good agreement with experimental shifts and the same is discussed in comparison with atomic charges, predicted by Mullikan and APT charge analysis. NBO analysis is carried out to picture the probable electronic transitions in the molecule.

  6. FT-IR, FT-Raman, NMR and UV-Vis spectra and DFT calculations of 5-bromo-2-ethoxyphenylboronic acid (monomer and dimer structures)

    NASA Astrophysics Data System (ADS)

    Sas, E. B.; Kose, E.; Kurt, M.; Karabacak, M.

    2015-02-01

    In this study, the Fourier Transform Infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectra of 5-bromo-2-ethoxyphenylboronic acid (5Br2EPBA) are recorded in the solid phase in the region 4000-400 cm-1 and 3500-10 cm-1, respectively. The 1H, 13C and DEPT nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The UV-Vis absorption spectrum of 5Br2EPBA is saved in the range of 200-400 nm in ethanol and water. The following theoretical calculations for monomeric and dimeric structures are supported by experimental results. The molecular geometry and vibrational frequencies in the ground state are calculated by using DFT methods with 6-31G(d,p) and 6-311G(d,p) basis sets. There are four conformers for the present molecule. The computational results diagnose the most stable conformer of 5Br2EPBA as Trans-Cis (TC) form. The complete assignments are performed on the basis of the total energy distribution (TED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method in parallel quantum solutions (PQS) program. The 1H and 13C NMR chemical shifts of 5Br2EPBA molecule are calculated by using the Gauge Invariant Atomic Orbital (GIAO) method in DMSO and gas phase for monomer and dimer structures of the most stable conformer. Moreover, electronic properties, such as the HOMO and LUMO energies (by TD-DFT and CIS methods) and molecular electrostatic potential surface (MEPs) are investigated. Stability of the molecule arising from hyper-conjugative interactions, charge delocalization is analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) properties and thermodynamic features are presented. All calculated results are compared with the experimental data of the title molecule. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the title molecule.

  7. FT-IR, FT-Raman, NMR and UV-Vis spectra and DFT calculations of 5-bromo-2-ethoxyphenylboronic acid (monomer and dimer structures).

    PubMed

    Sas, E B; Kose, E; Kurt, M; Karabacak, M

    2015-02-25

    In this study, the Fourier Transform Infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectra of 5-bromo-2-ethoxyphenylboronic acid (5Br2EPBA) are recorded in the solid phase in the region 4000-400 cm(-1) and 3500-10 cm(-1), respectively. The (1)H, (13)C and DEPT nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The UV-Vis absorption spectrum of 5Br2EPBA is saved in the range of 200-400 nm in ethanol and water. The following theoretical calculations for monomeric and dimeric structures are supported by experimental results. The molecular geometry and vibrational frequencies in the ground state are calculated by using DFT methods with 6-31G(d,p) and 6-311G(d,p) basis sets. There are four conformers for the present molecule. The computational results diagnose the most stable conformer of 5Br2EPBA as Trans-Cis (TC) form. The complete assignments are performed on the basis of the total energy distribution (TED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method in parallel quantum solutions (PQS) program. The (1)H and (13)C NMR chemical shifts of 5Br2EPBA molecule are calculated by using the Gauge Invariant Atomic Orbital (GIAO) method in DMSO and gas phase for monomer and dimer structures of the most stable conformer. Moreover, electronic properties, such as the HOMO and LUMO energies (by TD-DFT and CIS methods) and molecular electrostatic potential surface (MEPs) are investigated. Stability of the molecule arising from hyper-conjugative interactions, charge delocalization is analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) properties and thermodynamic features are presented. All calculated results are compared with the experimental data of the title molecule. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the title molecule.

  8. Synthesis, crystal structure analysis, spectral IR, NMR UV-Vis investigations, NBO and NLO of 2-benzoyl-N-(4-chlorophenyl)-3-oxo-3-phenylpropanamide with use of X-ray diffractions studies along with DFT calculations

    NASA Astrophysics Data System (ADS)

    Demir, Sibel; Sarioğlu, Ahmet Oral; Güler, Semih; Dege, Necmi; Sönmez, Mehmet

    2016-08-01

    The title compound, 2-benzoyl-N-(4-chlorophenyl)-3-oxo-3-phenylpropanamide compound (C22H16NO3Cl) has been synthesized and characterized by X-ray diffraction, IR, 1H and 13C NMR and UV-Vis spectra. Optimized geometrical structure, harmonic vibrational frequencies and chemical shifts were computed using hybrid-DFT (B3LYP and B3PW91) methods and 6-311G(d,p) as the basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The calculated optimized geometries, vibrational frequencies and 1H NMR chemical shift values are in strong agreement with experimentally measured values. UV-Vis spectrum of the title compound, was also recorded and the electronic properties, such as calculated energies, excitation energies, oscillator strengths, dipole moments and frontier orbital energies and band gap energies were computed with TDDFT-B3LYP methodolgy and using 6-311G(d,p) as the basis set. Furthermore, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), natural bond orbital (NBO) and non linear optical (NLO) properties were performed by using B3LYP/6-311G(d,p) level for the title compound.

  9. Synthesis, X-ray, NMR, FT-IR, UV/vis, DFT and TD-DFT studies of N-(4-chlorobutanoyl)-N'-(2-, 3- and 4-methylphenyl)thiourea derivatives.

    PubMed

    Abosadiya, Hamza M; Anouar, El Hassane; Hasbullah, Siti Aishah; Yamin, Bohari M

    2015-06-05

    A new isomers of thiourea derivatives, namely N-(4-chlorobutanoyl)-N'-(2-methylphenyl)-thiourea (1a), N-(4-chlorobutanoyl)-N'-(3-methylphenyl)thiourea (1b) and N-(4-chlorobutanoyl)-N'-(4-methylphenyl)thiourea (1c) have been synthesized by refluxing mixture of equimolar amounts of 4-chlorobutanoylisothiocyanate with 2, 3 or 4-toluidine, respectively. The three isomers were characterized by spectroscopic (UV/vis, FT-IR and NMR) and X-ray crystallography techniques. To investigate the isomerization effect on spectroscopic data, DFT and TD-DFT calculations have been carried out using five hybrid functionals (B3LYP, B3P86, CAM-B3LYP, M06-2X and PBE0) to predict UV/vis absorption bands (n→π∗ and π→π∗), (1)H and (13)C NMR chemical shifts, FT-IR vibration modes and X-ray parameters (bonds, bond angles and torsion angles) for 1a, 1b and 1c isomers. The results showed that the isomerization effect is significant on λ(MAX) absorption bands, while for IR and NMR the effect is negligible. In accordance with previous studies, B3LYP, B3P86 and PBE0 gave the most reliable to predict the excitation energies of thiourea derivatives.

  10. Antimycobacterial, antimicrobial activity, experimental (FT-IR, FT-Raman, NMR, UV-Vis, DSC) and DFT (transition state, chemical reactivity, NBO, NLO).

    PubMed

    Rawat, Poonam; Singh, R N; Ranjan, Alok; Ahmad, Sartaj; Saxena, Rajat

    2017-02-11

    As part of a study of pyrrole hydrazone, we have investigated quantum chemical calculations, molecular geometry, relative energy, vibrational properties and antimycobacterial/antimicrobial activity of pyrrole-2-carboxaldehyde isonicotinyl hydrazone (PCINH), by applying the density functional theory (DFT) and Hartree Fock (HF). Good reproduction of experimental values is obtained and with small percentage error in majority of the cases in comparison to theoretical result (DFT). The experimental FT-IR and Raman wavenumbers were compared with the respective theoretical values obtained from DFT calculations and found to agree well. In crystal structure studies the hydrated PCINH (syn-syn conformer) shows different conformation than from anhydrous form (syn-anti conformer). The rotational barrier between syn-syn and syn-anti conformers of PCINH is 12.7kcal/mol in the gas phase. In this work, use of FT-IR, FT-Raman, (1)H NMR, (13)C NMR and UV-Vis spectroscopies has been made for full characterization of PCINH. A detailed interpretation of the vibrational spectrum was carried out with the aid of normal coordinate analysis using single scaling factor. Our results support the hydrogen bonding pattern proposed by reported crystalline structure. The calculated nature of electronic transitions within molecule found to be π→π*. The electronic descriptors study indicates that PCINH can be used as robust synthon for synthesis of new heterocyclic compounds. The first static hyperpolarizability (β0) of PCINH is calculated as 33.89×10(-30)esu, (gas phase); 68.79×10(-30) (CHCl3), esu; 76.76×10(-30)esu (CH2Cl2), 85.16×10(-30)esu (DMSO). The solvent induced effects on the first static hyperpolarizability were studied and found to increase as dielectric constants of the solvents increases. Investigated molecule shows better NLO value than Para nitroaniline (PNA). The compound PCINH shows good antifungal and antibacterial activity against Aspergillus niger and gram

  11. Keto-enol tautomerism of (E)-2-[(3,4-dimethylphenylimino)methyl]-4-nitrophenol: Synthesis, X-ray, FT-IR, UV-Vis, NMR and quantum chemical characterizations

    NASA Astrophysics Data System (ADS)

    Özek Yıldırım, Arzu; Yıldırım, M. Hakkı; Albayrak Kaştaş, Çiǧdem

    2017-01-01

    (E)-2-((3,4-dimethylphenylimino)methyl)-4-nitrophenol, which is a new Schiff base compound, was synthesized and characterized by experimental and computational methods. Molecular geometry, harmonic oscillator model of aromaticity (HOMA) indices, intra- and inter-molecular interactions in the crystal structure were determined by using single crystal X-ray diffraction technique. The optimized structures, which are obtained by Gaussian and Slater type orbitals, were compared to experimental structures to determine how much correlation is found between the experimental and the calculated properties. Intramolecular and hyperconjugative interactions of bonds have been found by Natural Bond Orbital analysis. The experimental infrared spectrum of the compound has been analyzed in detail by the calculated infrared spectra and Potential Energy Distribution analysis. To find out about the correlation between the solvent polarity and the enol-keto equilibrium, experimental UV-Visible spectra of the compound were obtained in benzene, CHCl3, EtOH and DMSO solvents. In these solvents, the UV-Vis spectra and relaxed potential energy surface scan (PES) calculations have been performed to get more insight into the equilibrium dynamics. Solvent effects in UV-Vis and PES calculations have been taken into account by using Polarizable Continuum Modelling method. 1H and 13C NMR spectra of the compound (in DMSO) were analyzed. The computational study of nonlinear optical properties shows that the compound can be used for the development of nonlinear optical materials.

  12. Indole-containing new types of dyes and their UV-vis and NMR spectra and electronic structures: Experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Kuzu, Burak; Menges, Nurettin

    2016-06-01

    Indole containing dyes were synthesized via a simple method with high yield. These molecules have different colors and UV-vis spectra of them were recorded. Impact of solvents on absorbances was investigated and it was observed that basic solvent such as DMF and pyridine have blue shift. TD-DFT calculations were done and results were compared with experimental data. NMR data of molecules were analyzed and tautomeric forms of colorants and their ratio were determined. It was find out that two tautomers might be formed in solution, called indole and indolenine form. HOMO-LUMO and energy gaps were calculated and plotted. Furthermore, molecular electrostatic potentials were simulated to find out electrophilic and nucleophilic regions.

  13. Solvent and H/D isotope effects on the proton transfer pathways in heteroconjugated hydrogen-bonded phenol-carboxylic acid anions observed by combined UV-vis and NMR spectroscopy.

    PubMed

    Koeppe, Benjamin; Guo, Jing; Tolstoy, Peter M; Denisov, Gleb S; Limbach, Hans-Heinrich

    2013-05-22

    Heteroconjugated hydrogen-bonded anions A···H···X(-) of phenols (AH) and carboxylic/inorganic acids (HX) dissolved in CD2Cl2 and CDF3/CDF2Cl have been studied by combined low-temperature UV-vis and (1)H/(13)C NMR spectroscopy (UVNMR). The systems constitute small molecular models of hydrogen-bonded cofactors in proteins such as the photoactive yellow protein (PYP). Thus, the phenols studied include the PYP cofactor 4-hydroxycinnamic acid methyl thioester, and the more acidic 4-nitrophenol and 2-chloro-4-nitrophenol which mimic electronically excited cofactor states. It is shown that the (13)C chemical shifts of the phenolic residues of A···H···X(-), referenced to the corresponding values of A···H···A(-), constitute excellent probes for the average proton positions. These shifts correlate with those of the H-bonded protons, as well as with the H/D isotope effects on the (13)C chemical shifts. A combined analysis of UV-vis and NMR data was employed to elucidate the proton transfer pathways in a qualitative way. Dual absorption bands of the phenolic moiety indicate a double-well situation for the shortest OHO hydrogen bonds studied. Surprisingly, when the solvent polarity is low the carboxylates are protonated whereas the proton shifts toward the phenolic oxygens when the polarity is increased. This finding indicates that because of stronger ion-dipole interactions small anions are stabilized at high solvent polarity and large anions exhibiting delocalized charges at low solvent polarities. It also explains the large acidity difference of phenols and carboxylic acids in water, and the observation that this difference is strongly reduced in the interior of proteins when both partners form mutual hydrogen bonds.

  14. A palladium(II) complex containing both carbonyl and imine oxime ligands: Crystal structure, experimental and theoretical UV-vis, IR and NMR studies

    NASA Astrophysics Data System (ADS)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2013-05-01

    A new palladium(II) complex, [Pd(ppeieo)(inap)]·DMSO (ppeieo = (1E,2E)-phenyl-[(1-phenylethyl)imino]-ethanal oxime and inap = isonitrosoacetophenone) has been synthesized and characterized by elemental analysis, UV-vis, IR, NMR. X-ray diffraction analysis of the DMSO solvate of the complex shows that the palladium(II) ion is coordinated in a distorted square-planar geometry by ppeieo and inap, which is formed during the hydrolysis of ppeieo. DFT (B3LYP/LANL2DZ) calculations on the complex have been carried out to correlate geometry and spectroscopic properties such as electronic, vibrational and NMR chemical shifts. The complete vibrational frequency assignments were made and the calculation results were applied to simulate infrared spectra of the title compound which shows good agreement with observed spectra. The calculated HOMO and LUMO energies show that several transitions including the π → π* and charge transfer occur within the molecule. The chemical shifts reasonably correspond to the calculated spectra.

  15. A palladium(II) complex containing both carbonyl and imine oxime ligands: crystal structure, experimental and theoretical UV-vis, IR and NMR studies.

    PubMed

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T; Buyukgungor, Orhan

    2013-05-01

    A new palladium(II) complex, [Pd(ppeieo)(inap)]·DMSO (ppeieo=(1E,2E)-phenyl-[(1-phenylethyl)imino]-ethanal oxime and inap=isonitrosoacetophenone) has been synthesized and characterized by elemental analysis, UV-vis, IR, NMR. X-ray diffraction analysis of the DMSO solvate of the complex shows that the palladium(II) ion is coordinated in a distorted square-planar geometry by ppeieo and inap, which is formed during the hydrolysis of ppeieo. DFT (B3LYP/LANL2DZ) calculations on the complex have been carried out to correlate geometry and spectroscopic properties such as electronic, vibrational and NMR chemical shifts. The complete vibrational frequency assignments were made and the calculation results were applied to simulate infrared spectra of the title compound which shows good agreement with observed spectra. The calculated HOMO and LUMO energies show that several transitions including the π→π(*) and charge transfer occur within the molecule. The chemical shifts reasonably correspond to the calculated spectra.

  16. Synthesis, spectroscopic investigations (FT-IR, NMR, UV-Vis, and TD-DFT), and molecular docking of (E)-1-(benzo[d][1, 3]dioxol-6-yl)-3-(6-methoxynaphthalen-2-yl)prop-2-en-1-one

    NASA Astrophysics Data System (ADS)

    Therasa Alphonsa, A.; Loganathan, C.; Athavan Alias Anand, S.; Kabilan, S.

    2017-02-01

    The compound (E)-1-(benzo [d] [1, 3] dioxol-6-yl)-3-(6-methoxy naphthalen-2-yl) prop-2-en-1-one (AKN) was synthesized and characterized by FT-IR, NMR, and UV-Vis spectrometer. The optimized molecular geometry, bond lengths, bond angles, atomic charges, harmonic vibrational wave numbers and intensities of vibrational bonds of the title compound have been investigated by Time dependent- Density Functional Theory (TD-DFT) using a standard B3LYP method with 6-31 G (d, p) basis set available in the Gaussian 09W package. 1H and 13C NMR chemical shifts of the molecule were calculated using Gauge-independent atomic orbital method (GIAO). Experimental excitation energies of the molecules were matched with the theoretically calculated energies. The atomic charge distributions of the various atoms present in the AKN were obtained by Mulliken charge population analysis. The Molecular Electrostatic Potential (MEP) analysis reveals the sites for electrophilic attack and nucleophilic reactions in the molecule. The difference between the observed and scaled frequencies was small. The HOMO to LUMO transition implies an electron density transfer. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) analysis. The calculation results were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. To provide information about the interactions between human cytochrome protein and the novel compound theoretically, docking studies were carried out using Schrödinger software.

  17. Thiol-thione tautomeric analysis, spectroscopic (FT-IR, Laser-Raman, NMR and UV-vis) properties and DFT computations of 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule.

    PubMed

    Gökce, Halil; Öztürk, Nuri; Ceylan, Ümit; Alpaslan, Yelda Bingöl; Alpaslan, Gökhan

    2016-06-15

    In this study, the 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule (C7H6N4S) molecule has been characterized by using FT-IR, Laser-Raman, NMR and UV-vis spectroscopies. Quantum chemical calculations have been performed to investigate the molecular structure (thione-thiol tautomerism), vibrational wavenumbers, electronic transition absorption wavelengths in DMSO solvent and vacuum, proton and carbon-13 NMR chemical shifts and HOMOs-LUMOs energies at DFT/B3LYP/6-311++G(d,p) level for all five tautomers of the title molecule. The obtained results show that the calculated vibrational wavenumbers, NMR chemical shifts and UV-vis wavelengths are in a good agreement with experimental data.

  18. Thiol-thione tautomeric analysis, spectroscopic (FT-IR, Laser-Raman, NMR and UV-vis) properties and DFT computations of 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule

    NASA Astrophysics Data System (ADS)

    Gökce, Halil; Öztürk, Nuri; Ceylan, Ümit; Alpaslan, Yelda Bingöl; Alpaslan, Gökhan

    2016-06-01

    In this study, the 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule (C7H6N4S) molecule has been characterized by using FT-IR, Laser-Raman, NMR and UV-vis spectroscopies. Quantum chemical calculations have been performed to investigate the molecular structure (thione-thiol tautomerism), vibrational wavenumbers, electronic transition absorption wavelengths in DMSO solvent and vacuum, proton and carbon-13 NMR chemical shifts and HOMOs-LUMOs energies at DFT/B3LYP/6-311 ++G(d,p) level for all five tautomers of the title molecule. The obtained results show that the calculated vibrational wavenumbers, NMR chemical shifts and UV-vis wavelengths are in a good agreement with experimental data.

  19. Binuclear Pt-Tl bonded complex with square pyramidal coordination around Pt: a combined multinuclear NMR, EXAFS, UV-Vis, and DFT/TDDFT study in dimethylsulfoxide solution.

    PubMed

    Purgel, Mihály; Maliarik, Mikhail; Glaser, Julius; Platas-Iglesias, Carlos; Persson, Ingmar; Tóth, Imre

    2011-07-04

    The structure and bonding of a new Pt-Tl bonded complex formed in dimethylsulfoxide (dmso), (CN)(4)Pt-Tl(dmso)(5)(+), have been studied by multinuclear NMR and UV-vis spectroscopies, and EXAFS measurements in combination with density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations. This complex is formed following the equilibrium reaction Pt(CN)(4)(2-) + Tl(dmso)(6)(3+) ⇆ (CN)(4)Pt-Tl(dmso)(5)(+) + dmso. The stability constant of the Pt-Tl bonded species, as determined using (13)C NMR spectroscopy, amounts to log K = 2.9 ± 0.2. The (NC)(4)Pt-Tl(dmso)(5)(+) species constitutes the first example of a Pt-Tl bonded cyanide complex in which the sixth coordination position around Pt (in trans with respect to the Tl atom) is not occupied. The spectral parameters confirm the formation of the metal-metal bond, but differ substantially from those measured earlier in aqueous solution for complexes (CN)(5)Pt-Tl(CN)(n)(H(2)O)(x)(n-) (n = 0-3). The (205) Tl NMR chemical shift, δ = 75 ppm, is at extraordinary high field, while spin-spin coupling constant, (1)J(Pt-Tl) = 93 kHz, is the largest measured to date for a Pt-Tl bond in the absence of supporting bridging ligands. The absorption spectrum is dominated by two strong absorption bands in the UV region that are assigned to MMCT (Pt → Tl) and LMCT (dmso → Tl) bands, respectively, on the basis of MO and TDDFT calculations. The solution of the complex has a bright yellow color as a result of a shoulder present on the low energy side of the band at 355 nm. The geometry of the (CN)(4)Pt-Tl core can be elucidated from NMR data, but the particular stoichiometry and structure involving the dmso ligands are established by using Tl and Pt L(III)-edge EXAFS measurements. The Pt-Tl bond distance is 2.67(1) Å, the Tl-O bond distance is 2.282(6) Å, and the Pt-C-N entity is linear with Pt-C and Pt···N distances amounting to 1.969(6) and 3.096(6) Å, respectively. Geometry optimizations on

  20. UV-visible-DAD and 1H-NMR spectroscopy data fusion for studying the photodegradation process of azo-dyes using MCR-ALS.

    PubMed

    Fernández, Cristina; Pilar Callao, M; Larrechi, M Soledad

    2013-12-15

    The photodegradation process of three azo-dyes - Acid Orange 61, Acid Red 97 and Acid Brown 425 - was monitored simultaneously by ultraviolet-visible spectroscopy with diode array detector (UV-vis-DAD) and (1)H-nuclear magnetic resonance ((1)H-NMR). Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to obtain the concentration and spectral profile of the chemical compounds involved in the process. The analysis of the H-NMR data suggests there are more intermediate compounds than those obtained with the UV-vis-DAD data. The fusion of UV-vis-DAD and the (1)H-NMR signal before the multivariate analysis provides better results than when only one of the two detector signals was used. It was concluded that three degradation products were present in the medium when the three azo-dyes had practically degraded. This study is the first application of UV-vis-DAD and (1)H-NMR spectroscopy data fusion in this field and illustrates its potential as a quick method for evaluating the evolution of the azo-dye photodegradation process.

  1. Characterization of heroin samples by 1H NMR and 2D DOSY 1H NMR.

    PubMed

    Balayssac, Stéphane; Retailleau, Emmanuel; Bertrand, Geneviève; Escot, Marie-Pierre; Martino, Robert; Malet-Martino, Myriam; Gilard, Véronique

    2014-01-01

    Twenty-four samples of heroin from different illicit drug seizures were analyzed using proton Nuclear Magnetic Resonance ((1)H NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) (1)H NMR. A careful assignment and quantification of (1)H signals enabled a comprehensive characterization of the substances present in the samples investigated: heroin, its main related impurities (6-acetylmorphine, acetylcodeine, morphine, noscapine and papaverine) and cutting agents (caffeine and acetaminophen in nearly all samples as well as lactose, lidocaine, mannitol, piracetam in one sample only), and hence to establish their spectral signatures. The good agreement between the amounts of heroin, noscapine, caffeine and acetaminophen determined by (1)H NMR and gas chromatography, the reference method in forensic laboratories, demonstrates the validity of the (1)H NMR technique. In this paper, 2D DOSY (1)H NMR offers a new approach for a whole characterization of the various components of these complex mixtures.

  2. Synthesis, spectral (IR, UV-Vis and variable temperature NMR) characterization and crystal structure of (N-benzyl-N-furfuryldithicarbamato-S,S')(thiocyanato-N)(triphenylphosphine)nickel(II).

    PubMed

    Valarmathi, P; Thirumaran, S; Sarmal, Lovely; Kant, Rajni

    2014-08-14

    Planar (N-benzyl-N-furfuryldithiocarbamato-S,S')(thiocyanato-N)(triphenylphospine)nickel(II), [Ni(bfdtc)(NCS)(PPh3)], (1) was prepared from bis(N-benzyl-N-furfuryldithiocarbamato-S,S')nickel(II), [Ni(bfdtc)2], (2) and characterized by elemental analysis, cyclic voltammetry, electronic, IR and variable temperature (1)H and (13)C NMR spectra. For complex 1, the thioureide vCN value is shifted to higher wavenumber compared to 2 and N(13)CS2 carbon signal observed for 1 is additionally shielded compared to the parent complex 2, suggesting increased strength of the thioureide bond due to the presence of the π-accepting phosphine. In the room temperature (13)C NMR spectrum of 1, two pseudo doublets are observed in the aliphatic region. Variable temperature (13)C NMR spectral studies suggest that the fast thiocyanate exchange appears to be responsible for the appearance of pseudo doublets. Single crystal X-ray structural analysis of 1 and 2 confirm the presence of four coordinated nickel in a distorted square planar arrangement with the NiS2PN and NiS4 chromophores, respectively. The NiS bonds are symmetric in 2 (2.1914(14) and 2.2073(13)Å). But significant asymmetry in NiS bond distances was observed in 1 (2.2202(8)Å and 2.1841Å). This observation clearly supports the less effective trans effect of SCN(-) over PPh3. Cyclic voltammetric studies revealed easier reduction of nickel(II) to nickel(I) in complex 1 compared to 2.

  3. Synthesis, spectroscopic (UV-Vis, FT-IR and NMR), single crystal XRD of 3,5-diethyl -2,6-di(thiophen-2-yl)piperidin-4-on-1-ium picrate: A comprehensive experimental and computational study

    NASA Astrophysics Data System (ADS)

    Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.; Selvanayagam, S.; Sridhar, B.

    2017-01-01

    A piperidin-4-one containing picrate 3,5-diethyl -2,6-di(thiophen-2-yl)piperidin-4-on-1-ium picrate [3,5-DPPP] was synthesized. The molecular structure of 3,5-DPPP was confirmed by FT-IR, NMR, Uv-Vis, single crystal XRD analysis and DFT and HF methods with 6-31G(d,p) basis set. The XRD data confirm the transfer of protons from picric acid (O2) to piperidin-4-one ring (N1). The 3,5-DPPP compound is stabilized by the presence of intermolecular and intramolecular hydrogen bonds (N-H⋯O, C-H⋯S and C-H⋯O). Density functional theory and HF calculations have been used widely for calculating a wide variety of molecular properties such as optimized structure, FT-IR and Uv-Vis spectra, and provided reliable results which are in agreement with experimental data. The charge density data have been used to understand the properties of molecular systems. Furthermore, several quantum chemical insights have been obtained in the form of the total and partial density of states, the HOMO-LUMO energy gap and electrostatic potential map etc. In addition, the polarizability and first hyperpolarizability were calculated to show the potential applications of 3,5-DPPP in nonlinear optics.

  4. Complete (1) H NMR assignment of cedranolides.

    PubMed

    Perez-Hernandez, Nury; Gordillo-Roman, Barbara; Arrieta-Baez, Daniel; Cerda-Garcia-Rojas, Carlos M; Joseph-Nathan, Pedro

    2017-03-01

    Complete and unambiguous (1) H NMR chemical shift assignment of α-cedrene (2) and cedrol (9), as well as for α-pipitzol (1), isocedrol (10), and the six related compounds 3-8 has been established by iterative full spin analysis using the PERCH NMR software (PERCH Solutions Ltd., Kuopio, Finland). The total sets of coupling constants are described and correlated with the conformational equilibria of the five-membered ring of 1-10, which were calculated using the complete basis set method. Copyright © 2015 John Wiley & Sons, Ltd.

  5. UV/Vis/NIR Spectroelectrochemistry

    NASA Astrophysics Data System (ADS)

    Neudeck, Andreas; Marken, Frank; Compton, Richard G.

    Voltammetric techniques used in electrochemistry monitor the flow of current as a function of potential, time, and mass transport. A huge variety of different experiments are possible, giving information about reaction energies, reaction intermediates, and the kinetics of a process [1-4]. However, additional data are often required and are accessible, in particular, via in situ spectroelectrochemical approaches. By coupling a spectroscopic technique such as UV/Vis/NIR spectroscopy [5, 6] to an electrochemical experiment, a wealth of complementary information as a function of the potential, time, and mass transport is available. In a recently published book dedicated to spectroelectrochemical techniques [7] the diversity of methods and new chemical information obtained is apparent. Both spectroscopic information about short-lived unstable intermediates and spectroscopic information disentangling the composition of complex mixtures of reactants can be obtained. Figure II.6.1 shows a schematic diagram for the case of a computer-controlled potentiostat system connected to a conventional electrochemical cell (working electrode WE, reference electrode RE, counter electrode CE) and simultaneously controlling the emitter and detector of a spectrometer. This kind of experimental arrangement allows the electrochemical and the spectroscopic data to be recorded simultaneously and, therefore, in contrast to the analysis of two independent data sets, direct correlation of data as a function of time and potential is possible.

  6. Liquid-liquid extraction of metal ions by neutral phosphoramides. Part I. Extraction of uranyl ions from nitrate and sulphate media. Examination of extracted species by UV/VIS and {sup 31}P NMR spectroscopy

    SciTech Connect

    Rodehueser, L.; Rubini, P.R.; Bokolo, K.; Laakel, N.; Delpuech, J.J.

    1992-09-01

    The extraction of uranyl nitrate and uranyl sulphate from aqueous media by the neutral chelating diphosphoramides CH{sub 3}-N[P(O)(NMe{sub 2}){sub 2}]{sub 2} (NIPA) and its less hydrophilic homologs R-N[P(O)(NMe{sub 2}){sub 2}]{sub 2} (R = -C{sub 12}H{sub 25} (ODIPA) or -C{sub 16}H{sub 33} (OHDIPA)), diluted in CH{sub 3}NO{sub 2} or toluene, has been studied. In the presence of HNO{sub 3}, NaNO{sub 3}, NaCl, and Na{sub 2}SO{sub 4} as salting-out agents, extraction is generally excellent. Some of the extracted complex species have been identified by comparing their {sup 31}P NMR and UV/vis spectra with those of pure complexes of known structure. The results are compared with extractions using tri-n-butyl phosphate (TBP) as the complexing agent. 20 refs., 9 figs., 4 tabs.

  7. "Solvent Effects" in 1H NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  8. Teaching 1H NMR Spectrometry Using Computer Modeling.

    ERIC Educational Resources Information Center

    Habata, Yoichi; Akabori, Sadatoshi

    2001-01-01

    Molecular modeling by computer is used to display stereochemistry, molecular orbitals, structure of transition states, and progress of reactions. Describes new ideas for teaching 1H NMR spectroscopy using computer modeling. (Contains 12 references.) (ASK)

  9. IR, 1H NMR, mass, XRD and TGA/DTA investigations on the ciprofloxacin/iodine charge-transfer complex

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Hawary, W. F.; Moussa, Mohamed A. A.

    2011-05-01

    The charge-transfer complex (CTC) of ciprofloxacin drug (CIP) as a donor with iodine (I 2) as a sigma acceptor has been studied spectrophotometrically in CHCl 3. At maximum absorption bands, the stoichiometry of CIP:iodine system was found to be 1:1 ratio according to molar ratio method. The essential spectroscopic data like formation constant ( KCT), molar extinction coefficient ( ɛCT), standard free energy (Δ G°), oscillator strength ( f), transition dipole moment ( μ), resonance energy ( RN) and ionization potential ( ID) were estimated. The spectroscopic techniques such as IR, 1H NMR, mass and UV-vis spectra and elemental analyses (CHN) as well as TG-DTG and DTA investigations were used to characterize the chelating behavior of CIP/iodine charge-transfer complex. The iodine CT interaction was associated with a presence of intermolecular hydrogen bond. The X-ray investigation was carried out to investigate the iodine doping in the synthetic CT complex.

  10. Experimental and theoretical (FT-IR, FT-Raman, UV-vis, NMR) spectroscopic analysis and first order hyperpolarizability studies of non-linear optical material: (2E)-3-[4-(methylsulfanyl) phenyl]-1-(4-nitrophenyl) prop-2-en-1-one using density functional theory.

    PubMed

    Kumar, Amit; Deval, Vipin; Tandon, Poonam; Gupta, Archana; Deepak D'silva, E

    2014-09-15

    A combined experimental and theoretical investigation on FT-IR, FT-Raman, NMR, UV-vis spectra of a chalcone derivative (2E)-3-[4-(methylsulfanyl) phenyl]-1-(4-nitrophenyl) prop-2-en-1-one (4N4MSP) has been reported. 4N4MSP has two planar rings connected through conjugated double bond and it provides a necessary configuration to show non-linear optical (NLO) response. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) with B3LYP functional and 6-311++G(d,p) basis set combination. The analysis of the fundamental modes was made with the help of potential energy distribution (PED). Molecular electrostatic potential (MEP) surface was plotted over the geometry primarily for predicting sites and relative reactivities towards electrophilic and nucleophilic attack. The delocalization of electron density of various constituents of the molecule has been discussed with the aid of NBO analysis. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were calculated by time-dependent density functional theory (TD-DFT) and the results complement the experimental findings. The recorded and calculated 1H chemical shifts in gas phase and MeOD solution are gathered for reliable calculations of magnetic properties. Thermodynamic properties like heat capacity (C°p,m), entropy (S°m), enthalpy (H°m) have been calculated for the molecule at the different temperatures. Based on the finite-field approach, the non-linear optical (NLO) parameters such as dipole moment, mean polarizability, anisotropy of polarizability and first order hyperpolarizability of 4N4MSP molecule are calculated. The predicted first hyperpolarizability shows that the molecule has a reasonably good nonlinear optical (NLO) behavior.

  11. Temperature imaging by 1H NMR and suppression of convection in NMR probes

    PubMed

    Hedin; Furo

    1998-03-01

    A simple arrangement for suppressing convection in NMR probes is tested experimentally. Diffusion experiments are used to determine the onset of convection and 1H temperature imaging helps to rationalize the somewhat surprising results. A convenient new 1H NMR thermometer, CH2Br2 dissolved in a nematic thermotropic liquid crystal, is presented. Copyright 1998 Academic Press.

  12. Applications of 1H-NMR to Biodiesel Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

  13. Quantitative produced water analysis using mobile 1H NMR

    NASA Astrophysics Data System (ADS)

    Wagner, Lisabeth; Kalli, Chris; Fridjonsson, Einar O.; May, Eric F.; Stanwix, Paul L.; Graham, Brendan F.; Carroll, Matthew R. J.; Johns, Michael L.

    2016-10-01

    Measurement of oil contamination of produced water is required in the oil and gas industry to the (ppm) level prior to discharge in order to meet typical environmental legislative requirements. Here we present the use of compact, mobile 1H nuclear magnetic resonance (NMR) spectroscopy, in combination with solid phase extraction (SPE), to meet this metrology need. The NMR hardware employed featured a sufficiently homogeneous magnetic field, such that chemical shift differences could be used to unambiguously differentiate, and hence quantitatively detect, the required oil and solvent NMR signals. A solvent system consisting of 1% v/v chloroform in tetrachloroethylene was deployed, this provided a comparable 1H NMR signal intensity for the oil and the solvent (chloroform) and hence an internal reference 1H signal from the chloroform resulting in the measurement being effectively self-calibrating. The measurement process was applied to water contaminated with hexane or crude oil over the range 1-30 ppm. The results were validated against known solubility limits as well as infrared analysis and gas chromatography.

  14. 23Na and 1H NMR Microimaging of Intact Plants

    NASA Astrophysics Data System (ADS)

    Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

    2000-06-01

    23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  15. 23Na and (1)H NMR microimaging of intact plants.

    PubMed

    Olt, S; Krötz, E; Komor, E; Rokitta, M; Haase, A

    2000-06-01

    (23)Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using (23)Na as well as (1)H NMR microimaging. Experiments were performed at 11.75 T with a double resonant (23)Na-(1)H probehead. The probehead was homebuilt and equipped with a climate chamber. T(1) and T(2) of (23)Na were measured in the cross section of the hypocotyl. Within 85 min (23)Na images with an in-plane resolution of 156 x 156 micrometer were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, (23)Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  16. Blood characterization using UV/vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Mattley, Yvette D.; Mitrani-Gold, F.; Orton, S.; Bacon, Christina P.; Leparc, German F.; Bayona, M.; Potter, Robert L.; Garcia-Rubio, Luis H.

    1995-05-01

    The current methods used for typing blood involve an agglutination reaction which results from the association of specific antibodies with antigens present on the erythrocyte cell surface. While this method is effective, it requires involved laboratory procedures to detect the cell surface antigens. As an alternative technique, uv/vis spectroscopy has been investigated as a novel way to characterize and differentiate the blood types. Typing with this technique is based on spectral differences which appear throughout portions of both the ultraviolet and visible range. The origin of these spectral differences is unknown and presently under investigation. They may be due to intrinsic absorption differences at the molecular level, and/or they may be due to scattering differences brought about by either subtle variation in cell surface characteristics, cell shape or state of aggregation. As the background optical density in these samples is identified and accounted for, the spectral differences become more defined. This work and the continuation of this project will be included in a general database encompassing a wide range of blood samples. In addition, long term goals involve the investigation of diseased blood with the potential of providing a more rapid diagnosis for blood borne pathogens.

  17. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  18. Metabolomic insight into soy sauce through (1)H NMR spectroscopy.

    PubMed

    Ko, Bong-Kuk; Ahn, Hyuk-Jin; van den Berg, Frans; Lee, Cherl-Ho; Hong, Young-Shick

    2009-08-12

    Soy sauce, a well-known seasoning in Asia and throughout the world, consists of many metabolites that are produced during fermentation or aging and that have various health benefits. However, their comprehensive assessment has been limited due to targeted or instrumentally specific analysis. This paper presents for the first time a metabolic characterization of soy sauce, especially that aged up to 12 years, to obtain a global understanding of the metabolic variations through (1)H NMR spectroscopy coupled with multivariate pattern recognition techniques. Elevated amino acids and organic acids and the consumption of carbohydrate were associated with continuous involvement of microflora in aging for 12 years. In particular, continuous increases in the levels of betaine were found during aging for up to 12 years, demonstrating that microbial- or enzyme-related metabolites were also coupled with osmotolerant or halophilic bacteria present during aging. This work provides global insights into soy sauce through a (1)H NMR-based metabolomic approach that enhances the current understanding of the holistic metabolome and allows assessment of soy sauce quality.

  19. (1)H NMR spectra dataset and solid-state NMR data of cowpea (Vigna unguiculata).

    PubMed

    Alves Filho, Elenilson G; Silva, Lorena M A; Teofilo, Elizita M; Larsen, Flemming H; de Brito, Edy S

    2017-04-01

    In this article the NMR data from chemical shifts, coupling constants, and structures of all the characterized compounds were provided, beyond a complementary PCA evaluation for the corresponding manuscript (E.G. Alves Filho, L.M.A. Silva, E.M. Teofilo, F.H. Larsen, E.S. de Brito, 2017) [3]. In addition, a complementary assessment from solid-state NMR data was provided. For further chemometric analysis, numerical matrices from the raw (1)H NMR data were made available in Microsoft Excel workbook format (.xls).

  20. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

    PubMed Central

    Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

  1. Quantification of taurine in energy drinks using ¹H NMR.

    PubMed

    Hohmann, Monika; Felbinger, Christine; Christoph, Norbert; Wachter, Helmut; Wiest, Johannes; Holzgrabe, Ulrike

    2014-05-01

    The consumption of so called energy drinks is increasing, especially among adolescents. These beverages commonly contain considerable amounts of the amino sulfonic acid taurine, which is related to a magnitude of various physiological effects. The customary method to control the legal limit of taurine in energy drinks is LC-UV/vis with postcolumn derivatization using ninhydrin. In this paper we describe the quantification of taurine in energy drinks by (1)H NMR as an alternative to existing methods of quantification. Variation of pH values revealed the separation of a distinct taurine signal in (1)H NMR spectra, which was applied for integration and quantification. Quantification was performed using external calibration (R(2)>0.9999; linearity verified by Mandel's fitting test with a 95% confidence level) and PULCON. Taurine concentrations in 20 different energy drinks were analyzed by both using (1)H NMR and LC-UV/vis. The deviation between (1)H NMR and LC-UV/vis results was always below the expanded measurement uncertainty of 12.2% for the LC-UV/vis method (95% confidence level) and at worst 10.4%. Due to the high accordance to LC-UV/vis data and adequate recovery rates (ranging between 97.1% and 108.2%), (1)H NMR measurement presents a suitable method to quantify taurine in energy drinks.

  2. Continuous Flow 1H and 13C NMR Spectroscopy in Microfluidic Stripline NMR Chips

    PubMed Central

    2017-01-01

    Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline’s favorable geometry. In this study we demonstrate the possibility of dual-channel operation of a microfluidic stripline NMR setup showing one- and two-dimensional 1H, 13C and heteronuclear NMR experiments under continuous flow. We performed experiments on ethyl crotonate and menthol, using three different types of NMR chips aiming for straightforward microfluidic connectivity. The detection volumes are approximately 150 and 250 nL, while flow rates ranging from 0.5 μL/min to 15 μL/min have been employed. We show that in continuous flow the pulse delay is determined by the replenishment time of the detector volume, if the sample trajectory in the magnet toward NMR detector is long enough to polarize the spin systems. This can considerably speed up quantitative measurement of samples needing signal averaging. So it can be beneficial to perform continuous flow measurements in this setup for analysis of, e.g., reactive, unstable, or mass-limited compounds. PMID:28194934

  3. Continuous Flow (1)H and (13)C NMR Spectroscopy in Microfluidic Stripline NMR Chips.

    PubMed

    Oosthoek-de Vries, Anna Jo; Bart, Jacob; Tiggelaar, Roald M; Janssen, Johannes W G; van Bentum, P Jan M; Gardeniers, Han J G E; Kentgens, Arno P M

    2017-02-21

    Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline's favorable geometry. In this study we demonstrate the possibility of dual-channel operation of a microfluidic stripline NMR setup showing one- and two-dimensional (1)H, (13)C and heteronuclear NMR experiments under continuous flow. We performed experiments on ethyl crotonate and menthol, using three different types of NMR chips aiming for straightforward microfluidic connectivity. The detection volumes are approximately 150 and 250 nL, while flow rates ranging from 0.5 μL/min to 15 μL/min have been employed. We show that in continuous flow the pulse delay is determined by the replenishment time of the detector volume, if the sample trajectory in the magnet toward NMR detector is long enough to polarize the spin systems. This can considerably speed up quantitative measurement of samples needing signal averaging. So it can be beneficial to perform continuous flow measurements in this setup for analysis of, e.g., reactive, unstable, or mass-limited compounds.

  4. UV-VIS-NIR spectroscopy and microscopy of heterogeneous catalysts.

    PubMed

    Schoonheydt, Robert A

    2010-12-01

    This critical review article discusses the characterization of heterogeneous catalysts by UV-VIS-NIR spectroscopy and microscopy with special emphasis on transition metal ion containing catalysts. A review is given of the transitions, that can be observed in the UV-VIS-NIR region and the peculiarities of catalytic solids that have to be taken into account. This is followed by a short discussion of the techniques that have been developed over the years: diffuse reflectance spectroscopy, UV-VIS microscopy, in situ or operando spectroscopy, the combination of UV-VIS spectroscopy with other spectroscopic techniques, with chemometrics and with quantum chemistry. In the third part of this paper four successes of UV-VIS-NIR spectroscopy and microscopy are discussed; (1) coordination of transition metal ions to surface oxygens; (2) quantitative determination of the oxidation states of transition metal ions; (3) characterization of active sites and (4) study of the distribution of transition metal ions and carbocations in catalytic bodies, particles and crystals (104 references).

  5. Complete assignment of NMR data of 22 phenyl-1H-pyrazoles' derivatives.

    PubMed

    de Oliveira, Aline Lima; Alves de Oliveira, Carlos Henrique; Mairink, Laura Maia; Pazini, Francine; Menegatti, Ricardo; Lião, Luciano Morais

    2011-08-01

    Complete assignment of (1)H and (13)C NMR chemical shifts and J((1)H/(1)H and (1)H/(19)F) coupling constants for 22 1-phenyl-1H-pyrazoles' derivates were performed using the concerted application of (1)H 1D and (1)H, (13)C 2D gs-HSQC and gs-HMBC experiments. All 1-phenyl-1H-pyrazoles' derivatives were synthesized as described by Finar and co-workers. The formylated 1-phenyl-1H-pyrazoles' derivatives were performed under Duff's conditions.

  6. Determination of pKa values of tenoxicam from 1H NMR chemical shifts and of oxicams from electrophoretic mobilities (CZE) with the aid of programs SQUAD and HYPNMR.

    PubMed

    Rodríguez-Barrientos, Damaris; Rojas-Hernández, Alberto; Gutiérrez, Atilano; Moya-Hernández, Rosario; Gómez-Balderas, Rodolfo; Ramírez-Silva, María Teresa

    2009-12-15

    In this work it is explained, by the first time, the application of programs SQUAD and HYPNMR to refine equilibrium constant values through the fit of electrophoretic mobilities determined by capillary zone electrophoresis experiments, due to the mathematical isomorphism of UV-vis absorptivity coefficients, NMR chemical shifts and electrophoretic mobilities as a function of pH. Then, the pK(a) values of tenoxicam in H(2)O/DMSO 1:4 (v/v) have been obtained from (1)H NMR chemical shifts, as well as of oxicams in aqueous solution from electrophoretic mobilities determined by CZE, at 25 degrees C. These values are in very good agreement with those reported by spectrophotometric and potentiometric measurements.

  7. Derivatives of pyrazinecarboxylic acid: 1H, 13C and 15N NMR spectroscopic investigations.

    PubMed

    Holzer, Wolfgang; Eller, Gernot A; Datterl, Barbara; Habicht, Daniela

    2009-07-01

    NMR spectroscopic studies are undertaken with derivatives of 2-pyrazinecarboxylic acid. Complete and unambiguous assignment of chemical shifts ((1)H, (13)C, (15)N) and coupling constants ((1)H,(1)H; (13)C,(1)H; (15)N,(1)H) is achieved by combined application of various 1D and 2D NMR spectroscopic techniques. Unequivocal mapping of (13)C,(1)H spin coupling constants is accomplished by 2D (delta,J) long-range INEPT spectra with selective excitation. Phenomena such as the tautomerism of 3-hydroxy-2-pyrazinecarboxylic acid are discussed.

  8. Reliability of ^1^H NMR analysis for assessment of lipid oxidation at frying temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The reliability of a method using ^1^H NMR analysis for assessment of oil oxidation at a frying temperature was examined. During heating and frying at 180 °C, changes of soybean oil signals in the ^1^H NMR spectrum including olefinic (5.16-5.30 ppm), bisallylic (2.70-2.88 ppm), and allylic (1.94-2.1...

  9. Synthesis, structural, and spectroscopic (FT-IR, NMR, and UV) Characterization of 1-(Cyclohexylmethyl)-2-(pyridin-2-yl)-1 H-benzo[ d]imidazole by experimental techniques and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Özdemir, Namık; Dayan, Osman; Demirmen, Selin

    2016-05-01

    The title compound ( II), 1-(cyclohexylmethyl)-2-(pyridin-2-yl)-1 H-benzo[ d]imidazole (C19H21N3), was synthesized via N-alkylation of 2-(pyridin-2-yl)-1 H-benzo[ d]imidazole ( I). Both compounds I and II were characterized by IR, NMR and UV-vis spectroscopy. Solid-state structure of compound II was determined by single-crystal X-ray diffraction technique. Furthermore, quantum chemical calculations employing density functional theory (DFT/B3LYP) method with the 6-311++ G( d, p) basis set were performed for the theoretical characterization of the molecular and spectroscopic features of the compounds. Using the TD-DFT method, electronic absorption spectra of the compounds have been predicted at same level. When the obtained results were compared with the experimental findings, it is seen that theoretical results support the experimental data and a good agreement exists between them.

  10. UV-VIS absorption spectroscopy: Lambert-Beer reloaded.

    PubMed

    Mäntele, Werner; Deniz, Erhan

    2017-02-15

    UV-VIS absorption spectroscopy is used in almost every spectroscopy laboratory for routine analysis or research. All spectroscopists rely on the Lambert-Beer Law but many of them are less aware of its limitations. This tutorial discusses typical problems in routine spectroscopy that come along with technical limitations or careless selection of experimental parameters. Simple rules are provided to avoid these problems.

  11. UV-VIS absorption spectroscopy: Lambert-Beer reloaded

    NASA Astrophysics Data System (ADS)

    Mäntele, Werner; Deniz, Erhan

    2017-02-01

    UV-VIS absorption spectroscopy is used in almost every spectroscopy laboratory for routine analysis or research. All spectroscopists rely on the Lambert-Beer Law but many of them are less aware of its limitations. This tutorial discusses typical problems in routine spectroscopy that come along with technical limitations or careless selection of experimental parameters. Simple rules are provided to avoid these problems.

  12. 1H NMR investigation of thermally triggered insulin release from poly(N-isopropylacrylamide) microgels.

    PubMed

    Nolan, Christine M; Gelbaum, Leslie T; Lyon, L Andrew

    2006-10-01

    We describe investigations of insulin release from thermoresponsive microgels using variable temperature (1)H NMR. Microgel particles composed of poly(N-isopropylacrylamide) were loaded with the peptide via a swelling technique, and this method was compared to simple equilibrium partitioning. Variable temperature (1)H NMR studies suggest that the swelling loading method results in enhanced entrapment of the peptide versus equilibrium partitioning. A centrifugation-loading assay supports this finding. Pseudo-temperature jump (1)H NMR measurements suggest that the insulin release rate is partially decoupled from microgel collapse. These types of direct release investigations could prove to be useful methods in the future design of controlled macromolecule drug delivery devices.

  13. Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

    PubMed Central

    Liu, Yang; Liu, Zhaoxia; Yang, Huaxin

    2016-01-01

    Quantitative nuclear magnetic resonance (qNMR) is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR) and only a few fluorine qNMR (19F qNMR) were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes. PMID:27688925

  14. Protein-Observed Fluorine NMR Is a Complementary Ligand Discovery Method to (1)H CPMG Ligand-Observed NMR.

    PubMed

    Urick, Andrew K; Calle, Luis Pablo; Espinosa, Juan F; Hu, Haitao; Pomerantz, William C K

    2016-11-18

    To evaluate its potential as a ligand discovery tool, we compare a newly developed 1D protein-observed fluorine NMR (PrOF NMR) screening method with the well-characterized ligand-observed (1)H CPMG NMR screen. We selected the first bromodomain of Brd4 as a model system to benchmark PrOF NMR because of the high ligandability of Brd4 and the need for small molecule inhibitors of related epigenetic regulatory proteins. We compare the two methods' hit sensitivity, triaging ability, experiment speed, material consumption, and the potential for false positives and negatives. To this end, we screened 930 fragment molecules against Brd4 in mixtures of five and followed up these studies with mixture deconvolution and affinity characterization of the top hits. In selected examples, we also compare the environmental responsiveness of the (19)F chemical shift to (1)H in 1D-protein observed (1)H NMR experiments. To address concerns of perturbations from fluorine incorporation, ligand binding trends and affinities were verified via thermal shift assays and isothermal titration calorimetry. We conclude that for the protein understudy here, PrOF NMR and (1)H CPMG have similar sensitivity, with both being effective tools for ligand discovery. In cases where an unlabeled protein can be used, 1D protein-observed (1)H NMR may also be effective; however, the (19)F chemical shift remains significantly more responsive.

  15. Alternative determination of blood alcohol concentration by (1)H NMR spectroscopy.

    PubMed

    Zailer, Elina; Diehl, Bernd W K

    2016-02-05

    A rapid, accurate and specific proton nuclear magnetic resonance ((1)H NMR) spectroscopic method is developed to determine ethanol in blood, known as the blood alcohol concentration (BAC). The limits of detection and quantification are 0.02g/L and 0.07g/L, respectively. The (1)H NMR spectra show linearity for whole blood and serum samples of a concentration range of 0.00-3.00g/L (R(2)>0.9995). The (1)H NMR method is applied and validated for whole blood as the sample media. Real driving under influence case samples are analyzed with the reference enzyme-based alcohol dehydrogenase and headspace gas chromatography techniques by the Forensic Medicine in Bonn. The reference results are compared with the (1)H NMR spectroscopic results. The validation and comparison indicate that (1)H NMR is suitable for the quantification of BAC in whole blood. This technique has the advantages of automated analysis with good measurement precision and fast sample throughput. A drop of blood (V=20μL) is adequate for an analysis leading to a possible simplification of the sample collection. Due to the non-destructive method, follow-up examinations by (1)H NMR spectroscopy or DNA determinations by different techniques (PCR, in situ hybridization) are possible in resolving legal disputes.

  16. Complete Assignment of (1)H-NMR Resonances of the King Cobra Neurotoxin CM-11.

    PubMed

    Pang, Yu-Xi; Liu, Wei-Dong; Liu, Ai-Zhuo; Pei, Feng-Kui

    1997-01-01

    The king cobra (Ophiophagus Hannah) neurotoxin CM-Il is long-chain peptide with 72 amino acid residues. Its complete assignment of (1)H-NMR resonances was obtained using various 2D-NMR technologies, including DQF-COSY, clean-TOCSY and NOESY.

  17. 1H and 13C NMR assignments for two new angular furanocoumarin glycosides from Peucedanum praeruptorum.

    PubMed

    Chang, Haitao; Okada, Yoshihito; Okuyama, Toru; Tu, Pengfei

    2007-07-01

    Two novel angular-type furanocoumarin glycosides, peucedanoside A (1) and peucedanoside B (2), along with a known compound apterin (3), were isolated from the roots of Peucedanum praeruptorum Dunn. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments including DEPT, HSQC, HMBC and ROESY.

  18. Preliminary 1H NMR study on archaeological waterlogged wood.

    PubMed

    Maccotta, Antonella; Fantazzini, Paola; Garavaglia, Carla; Donato, Ines D; Perzia, Patrizia; Brai, Maria; Morreale, Filippa

    2005-01-01

    Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood.

  19. Study the chemical composition and biological outcomes resulting from the interaction of the hormone adrenaline with heavy elements: Infrared, Raman, electronic, 1H NMR, XRD and SEM studies

    NASA Astrophysics Data System (ADS)

    Ibrahim, Omar B.; Mohamed, Mahmoud A.; Refat, Moamen S.

    2014-01-01

    Heavy metal adrenaline complexes formed from the reaction of adrenaline with Al3+, Zn2+, Sn2+, Sb3+, Pb2+and Bi3+ ions in methanolic solvent at 60 °C. The final reaction products have been isolated and characterization using elemental analyses (% of carbon, hydrogen and nitrogen), conductivity measurements, mid infrared, Raman laser, UV-Vis, 1H NMR spectra, X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). Upon the spectroscopic, conductivity and elemental analyses, the stoichiometric reactions indicated that the data obtained refer to 1:2 (M:L) for Zn2+, Sn2+, Pb2+and Bi3+ complexes [Zn(Adr)2(Cl)2], [Sn(Adr)2]Cl2, [Pb(Adr)2](NO3)2 and [Bi(Adr)2(Cl)2]Cl, while the molar ratio 1:3 (M:L) for Al3+ and Sb3+ with formulas [Al(Adr)3](NO3)3 and [Sb(Adr)3]Cl3. The infrared and Raman laser spectra interpreted the mode of interactions which associated through the two phenolic groups of catechol moiety. The adrenaline chelates have been screened for their in vitro antibacterial activity against four bacteria, Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial and antifungal activities than the free adrenaline chelate.

  20. Syntheses, structures, and 1H, 13C{1H} and 119Sn{1H} NMR chemical shifts of a family of trimethyltin alkoxide, amide, halide and cyclopentadienyl compounds

    DOE PAGES

    Lichtscheidl, Alejandro G.; Janicke, Michael T.; Scott, Brian L.; ...

    2015-08-21

    The synthesis and full characterization, including Nuclear Magnetic Resonance (NMR) data (1H, 13C{1H} and 119Sn{1H}), for a series of Me3SnX (X = O-2,6-tBu2C6H3 (1), (Me3Sn)N(2,6-iPr2C6H3) (3), NH-2,4,6-tBu3C6H2 (4), N(SiMe3)2 (5), NEt2, C5Me5 (6), Cl, Br, I, and SnMe3) compounds in benzene-d6, toluene-d8, dichloromethane-d2, chloroform-d1, acetonitrile-d3, and tetrahydrofuran-d8 are reported. The X-ray crystal structures of Me3Sn(O-2,6-tBu2C6H3) (1), Me3Sn(O-2,6-iPr2C6H3) (2), and (Me3Sn)(NH-2,4,6-tBu3C6H2) (4) are also presented. As a result, these compiled data complement existing literature data and ease the characterization of these compounds by routine NMR experiments.

  1. 1H-NMR and 13C-NMR lipid profiles of human renal tissues.

    PubMed

    Tugnoli, V; Bottura, G; Fini, G; Reggiani, A; Tinti, A; Trinchero, A; Tosi, M R

    2003-01-01

    Lipids from human renal tissues are studied by means of (1)H- and (13)C-NMR spectroscopy. The total lipid fractions obtained from healthy kidneys, malignant renal cell carcinomas, and benign oncocytomas are characterized and analyzed to elucidate the main differences between the functional and neoplastic tissues. In all cases the lipid components are well identified. The healthy kidney is characterized by high amounts of triglycerides and the presence of cholesterol in its free form. On the contrary, renal cell carcinomas contain high amounts of cholesterol that are almost completely esterified as oleate, suggesting an intracellular localization of the cholesteryl esters synthesis. Cholesteryl esters are considered markers of renal cell carcinomas, thus supporting recent theories that these compounds play a leading role in cell proliferation. Oncocytomas are particularly rich in phosphatidylcholine and, analogous to the healthy kidney, are completely lacking in cholesteryl esters. Healthy kidneys and oncocytomas appear to have other similarities if compared with renal cell carcinomas: a very high fatty acyl/cholesterol ratio, the presence of dolichols, and a higher grade of unsaturation. The (13)C data suggest a new method for the direct evaluation of the saturated/unsaturated fatty acyl ratio.

  2. Quantitative Determination of Carthamin in Carthamus Red by 1H-NMR Spectroscopy.

    PubMed

    Yoshida, Takamitsu; Terasaka, Kazuyoshi; Kato, Setsuko; Bai, Fan; Sugimoto, Naoki; Akiyama, Hiroshi; Yamazaki, Takeshi; Mizukami, Hajime

    2013-01-01

    Carthamus Red is a food colorant prepared from the petals of Carthamus tinctorius (Asteraceae) whose major pigment is carthamin. Since an authentic carthamin standard is difficult to obtain commercially for the preparation of calibration curves in HPLC assays, we applied (1)H-NMR spectroscopy to the quantitative determination of carthamin in commercial preparations of Carthamus Red. Carthamus Red was repeatedly extracted in methanol and the extract was dissolved in pyridine-d(5) containing hexamethyldisilane (HMD) prior to (1)H-NMR spectroscopic analysis. The carthamin contents were calculated from the ratios of singlet signal intensities at approximately σ: 9.3 derived from H-16 of carthamin to those of the HMD signal at σ: 0. The integral ratios exhibited good repeatability among NMR spectroscopic analyses. Both the intra-day and inter-day assay variations had coefficients of variation of <5%. Based on the coefficient of absorption, the carthamin contents of commercial preparations determined by (1)H-NMR spectroscopy correlated well with those determined by colorimetry, although the latter were always approximately 1.3-fold higher than the former, irrespective of the Carthamus Red preparations. In conclusion, the quantitative (1)H-NMR spectroscopy used in the present study is simple and rapid, requiring no carthamin standard for calibration. After HMD concentration has been corrected using certified reference materials, the carthamin contents determined by (1)H-NMR spectroscopy are System of Units (SI)-traceable.

  3. Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

    PubMed Central

    Okuom, Macduff O.; Wilson, Mark V.; Jackson, Abby; Holmes, Andrea E.

    2014-01-01

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  4. Conformational evaluation and detailed 1H and 13C NMR assignments of eremophilanolides.

    PubMed

    Burgueño-Tapia, Eleuterio; Hernández, Luis R; Reséndiz-Villalobos, Adriana Y; Joseph-Nathan, Pedro

    2004-10-01

    Extensive application of 1D and 2D NMR methodology, combined with molecular modeling, allowed the complete 1H and 13C NMR assignments of eremophilanolides from Senecio toluccanus. Comparison of the experimental 1H, 1H coupling constant values with those generated employing a generalized Karplus-type relationship, using dihedral angles extracted from MMX and DFT calculations, revealed that the epoxidized eremophilanolides 1 and 2 show conformational rigidity at room temperature, whereas molecules 3-6, containing an isolated double bond, are conformationally mobile.

  5. Digital NMR Profiles as Building Blocks: Assembling 1H Fingerprints of Steviol Glycosides

    PubMed Central

    Napolitano, José G.; Simmler, Charlotte; McAlpine, James B.; Lankin, David C.; Chen, Shao-Nong; Pauli, Guido F.

    2015-01-01

    This report describes a fragment-based approach to the examination of congeneric organic compounds by NMR spectroscopy. The method combines the classic interpretation of 1D- and 2D-NMR data sets with contemporary computer-assisted NMR analysis. Characteristic NMR profiles of key structural motifs were generated by 1H iterative full spin analysis and then joined together as building blocks to recreate the 1H NMR spectra of increasingly complex molecules. To illustrate the methodology described, a comprehensive analysis of steviol (1), seven steviol glycosides (2–8) and two structurally related isosteviol compounds (9, 10) was carried out. The study also assessed the potential impact of this method on relevant aspects of natural product research including structural verification, chemical dereplication, and mixture analysis. PMID:25714117

  6. Infrared, Raman and NMR spectra, conformational stability, normal coordinate analysis and B3LYP calculations of 5-Amino-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde

    NASA Astrophysics Data System (ADS)

    Bahgat, Khaled; EL-Emary, Talaat

    2013-02-01

    FT Raman and IR spectra of the crystallized biologically active molecule, 5-Amino-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (5-APHC, C11H11N3O) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies of 5-APHC have been investigated with the help of B3LYP density functional theory (DFT) method with 6-31G(d) and 6-311+G(d,p) as basis set. The calculated molecular geometry has been compared with the experimental data. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQM) technique. The optimized geometry shows the co-planarity of the aldehyde group with pyrazole ring. Potential energy surface (PES) scan studies has also been carried out by ab initio calculations with B3LYP/6-311+G(d,p) basis set. The red shifting of NH2 stretching wavenumber indicates the formation of N-H⋯O hydrogen bonding. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Vis spectrum of the compound was recorded in the region 200-400 nm and the electronic properties HOMO and LUMO energies were calculated by time-dependent TD-DFT approach. Mulliken charges of the 5-APHC molecule was also calculated and interpreted.

  7. [Design of a portable UV-Vis spectrophotometer].

    PubMed

    Wan, Feng; Sun, Hong-wei; Fan, Shi-fu

    2006-04-01

    In the present paper, a method for how to design a portable UV-Vis spectrophotometer is introduced. The Hamamatsu multichannel detector S3904-1024Q and a flat field concave grating are employed to design a miniaturized dispersion system. In order to solve the contradiction between the spectral width and energy-utilizing ratio of the light source, a multi-band optical fiber is employed, one side of which is arranged to be rectangle as the entrance slit. The touch screen is employed as the input and output system of the spectrophotometer, and the miniaturized fiber-optic UV-Vis light source is employed as the light source. The research results and testing results of the prototype show that the new spectrophotometer based on the authors' new method is of miniaturization in volume(190 mm x 170 mm x 100 mm), can realize multi-wavelength-detection on-line, and is easily handled (touch screen control), and its performance accords with the Chinese national standard.

  8. 1H NMR quantitative determination of photosynthetic pigments from green beans (Phaseolus vulgaris L.).

    PubMed

    Valverde, Juan; This, Hervé

    2008-01-23

    Using 1H nuclear magnetic resonance spectroscopy (1D and 2D), the two types of photosynthetic pigments (chlorophylls, their derivatives, and carotenoids) of "green beans" (immature pods of Phaseolus vulgaris L.) were analyzed. Compared to other analytical methods (light spectroscopy or chromatography), 1H NMR spectroscopy is a fast analytical way that provides more information on chlorophyll derivatives (allomers and epimers) than ultraviolet-visible spectroscopy. Moreover, it gives a large amount of data without prior chromatographic separation.

  9. Conformational studies by 1H and 13C NMR of lisinopril

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yohko; Ishi, Tomoko

    1993-10-01

    Lisinopril, N-N-[( s-1-carboxy-3-phenylpropyl]- L-lysyl- L-proline) (MK-521), is an inhibitor of angiotensin-converting enzyme and a new drug for the treatment of hypertension. 1H and 13C NMR studies have shown that the s-cis equilibrium about the amide bond is strongly dependent on the configuration of the chiral centres. Vicinal coupling constants of stereochemical significance were obtained in deuterated solvent using NMR techniques. Comparison with values calculated for lisinopril using potential energy calculations and NMR show that lisinopril exists in preferred optimum conformation in solution.

  10. Importance of Purity Evaluation and the Potential of Quantitative 1H NMR as a Purity Assay

    PubMed Central

    2015-01-01

    In any biomedical and chemical context, a truthful description of chemical constitution requires coverage of both structure and purity. This qualification affects all drug molecules, regardless of development stage (early discovery to approved drug) and source (natural product or synthetic). Purity assessment is particularly critical in discovery programs and whenever chemistry is linked with biological and/or therapeutic outcome. Compared with chromatography and elemental analysis, quantitative NMR (qNMR) uses nearly universal detection and provides a versatile and orthogonal means of purity evaluation. Absolute qNMR with flexible calibration captures analytes that frequently escape detection (water, sorbents). Widely accepted structural NMR workflows require minimal or no adjustments to become practical 1H qNMR (qHNMR) procedures with simultaneous qualitative and (absolute) quantitative capability. This study reviews underlying concepts, provides a framework for standard qHNMR purity assays, and shows how adequate accuracy and precision are achieved for the intended use of the material. PMID:25295852

  11. Probing degradation in complex engineering silicones by 1H multiple quantum NMR

    SciTech Connect

    Maxwell, R S; Chinn, S C; Giuliani, J; Herberg, J L

    2007-09-05

    Static {sup 1}H Multiple Quantum Nuclear Magnetic Resonance (MQ NMR) has recently been shown to provide detailed insight into the network structure of pristine silicon based polymer systems. The MQ NMR method characterizes the residual dipolar couplings of the silicon chains that depend on the average molecular weight between physical or chemical constraints. Recently, we have employed MQ NMR methods to characterize the changes in network structure in a series of complex silicone materials subject to numerous degradation mechanisms, including thermal, radiative, and desiccative. For thermal degradation, MQ NMR shows that a combination of crosslinking due to post-curing reactions as well as random chain scissioning reactions occurs. For radiative degradation, the primary mechanisms are via crosslinking both in the network and at the interface between the polymer and the inorganic filler. For samples stored in highly desiccating environments, MQ NMR shows that the average segmental dynamics are slowed due to increased interactions between the filler and the network polymer chains.

  12. Fluorescence and UV-vis Spectroscopy of Synovial Fluids

    NASA Astrophysics Data System (ADS)

    Pinti, Marie J.; Stojilovic, Nenad; Kovacik, Mark W.

    2009-10-01

    Total joint arthroplasty involves replacing the worn cartilaginous surfaces of the joint with man-made materials that are designed to be biocompatible and to withstand mechanical stresses. Commonly these bearing materials consist of metallic alloys (TiAlV or CoCrMo) and UHMWPE. Following joint arthroplasty, the normal generation of micro-metallic wear debris particles that dislodge from the prosthesis has been shown to cause inflammatory aseptic osteolysis (bone loss) that ultimately results in the failure of the implant. Here we report our results on the novel use of Fluorescence and UV-vis spectroscopy to investigate the metallic content of synovial fluid specimens taken from postoperative total knee arthroplasties. Preliminary finding showed presence of alumina and chromium is some specimens. The ability to detect and monitor the wear rate of these implants could have far reaching implications in the prevention of metallic wear-debris induced osteolysis and impending implant failure.

  13. Simultaneous 19F-1H medium resolution NMR spectroscopy for online reaction monitoring

    NASA Astrophysics Data System (ADS)

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

    2014-12-01

    Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16″ fluorinated ethylene propylene (FEP) tube with an ID of 0.04″ (1.02 mm) was used as a flow cell in combination with a 5 mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a 1H Larmor frequency of 43.32 MHz and 40.68 MHz for 19F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating 19F and 1H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500 MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16″ FEP tube set-up with an ID of 1.02 mm was characterised regarding the limit of detection (LOQ (1H) = 0.335 mol L-1 and LOQ (19F) = 0.130 mol L-1 for trifluoroethanol in

  14. A novel one-pot synthesis of heterocyclic compound (4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one): Structural (X-ray and DFT) and spectroscopic (FT-IR, NMR, UV-Vis and Mass) characterization Studies

    NASA Astrophysics Data System (ADS)

    Özdemir, Mecit; Sönmez, Mehmet; Şen, Fatih; Dinçer, Muharrem; Özdemir, Namık

    2015-02-01

    In this study, the title compound named as 4-benzoyl-5-phenyl-2-(pyridin-2-yl)-3,3a-dihydropyrazolo[1,5-c]pyrimidin-7(6H)-one (C24H18N4O2) was both experimentally and theoretically investigated. The compound was synthesized and characterized by FT-IR, NMR (1H NMR, 13C NMR and HETCOR-NMR), Mass spectroscopies and single-crystal X-ray diffraction methods. The compound crystallizes in the monoclinic space group P21/n with a = 6.1402 (3) Å, b = 21.4470 (15) Å, c = 15.0049 (8) Å and β = 97.407 (4)°. The molecular geometry was obtained from the X-ray structure determination optimized using density functional theory (DFT/B3LYP) method with the 6-31+G(d, p) basis set in ground state. From the optimized structure, geometric parameters, vibrational wavenumbers and chemical shifts of molecule were obtained. Experimental measurements were compared with its corresponding the calculated data. An excellent harmony between the two data was ascertained. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs) and non-linear optical (NLO) properties of the title molecule were investigated by theoretical calculations at the B3LYP/6-31+G(d, p) level.

  15. Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform.

    PubMed

    Hanson, Cynthia; Israelsen, Nathan D; Sieverts, Michael; Vargis, Elizabeth

    2016-11-10

    Immunoassays are used to detect proteins based on the presence of associated antibodies. Because of their extensive use in research and clinical settings, a large infrastructure of immunoassay instruments and materials can be found. For example, 96- and 384-well polystyrene plates are available commercially and have a standard design to accommodate ultraviolet-visible (UV-Vis) spectroscopy machines from various manufacturers. In addition, a wide variety of immunoglobulins, detection tags, and blocking agents for customized immunoassay designs such as enzyme-linked immunosorbent assays (ELISA) are available. Despite the existing infrastructure, standard ELISA kits do not meet all research needs, requiring individualized immunoassay development, which can be expensive and time-consuming. For example, ELISA kits have low multiplexing (detection of more than one analyte at a time) capabilities as they usually depend on fluorescence or colorimetric methods for detection. Colorimetric and fluorescent-based analyses have limited multiplexing capabilities due to broad spectral peaks. In contrast, Raman spectroscopy-based methods have a much greater capability for multiplexing due to narrow emission peaks. Another advantage of Raman spectroscopy is that Raman reporters experience significantly less photobleaching than fluorescent tags(1). Despite the advantages that Raman reporters have over fluorescent and colorimetric tags, protocols to fabricate Raman-based immunoassays are limited. The purpose of this paper is to provide a protocol to prepare functionalized probes to use in conjunction with polystyrene plates for direct detection of analytes by UV-Vis analysis and Raman spectroscopy. This protocol will allow researchers to take a do-it-yourself approach for future multi-analyte detection while capitalizing on pre-established infrastructure.

  16. Sudan dyes in adulterated saffron (Crocus sativus L.): Identification and quantification by (1)H NMR.

    PubMed

    Petrakis, Eleftherios A; Cagliani, Laura R; Tarantilis, Petros A; Polissiou, Moschos G; Consonni, Roberto

    2017-02-15

    Saffron, the dried red stigmas of Crocus sativus L., is considered as one of the most expensive spices worldwide, and as such, it is prone to adulteration. This study introduces an NMR-based approach to identify and determine the adulteration of saffron with Sudan I-IV dyes. A complete (1)H and (13)C resonance assignment for Sudan I-IV, achieved by two-dimensional homonuclear and heteronuclear NMR experiments, is reported for the first time. Specific different proton signals for the identification of each Sudan dye in adulterated saffron can be utilised for quantitative (1)H NMR (qHNMR), a well-established method for quantitative analysis. The quantification of Sudan III, as a paradigm, was performed in varying levels (0.14-7.1g/kg) by considering the NMR signal occurring at 8.064ppm. The high linearity, accuracy and rapidity of investigation enable high resolution (1)H NMR spectroscopy to be used for evaluation of saffron adulteration with Sudan dyes.

  17. Hyphenation of capillary HPLC to microcoil (1)H NMR spectroscopy for the determination of tocopherol homologues.

    PubMed

    Krucker, Manfred; Lienau, Annette; Putzbach, Karsten; Grynbaum, Marc David; Schuler, Paul; Albert, Klaus

    2004-05-01

    Highly selective reversed phases (C(30) phases) are self-packed in 250 microm inner diameter fused-silica capillaries and employed for capillary HPLC separation of shape-constrained natural compounds (tocopherol homologues, vitamin E). Miniaturized hyphenated systems such as capillary HPLC-ESI-MS (positive ionization mode) and, with special emphasis, continuous-flow capillary HPLC- NMR are used for structural determination of the separated compounds. Despite the small amount of sample available (1.33 microg of each tocopherol), the authors have been able to monitor the capillary HPLC separation under continuous-flow (1)H NMR conditions, thus allowing an immediate peak identification. Further structural assignment was carried out in the stopped-flow NMR mode as shown, for example, by a 2D (1)H,(1)H COSY NMR spectrum of alpha-tocopherol. We demonstrate in this paper the considerable potential of hyphenated capillary separations coupled to MS and NMR for the investigation of restricted amounts of sample.

  18. Molecular Structures from [superscript 1]H NMR Spectra: Education Aided by Internet Programs

    ERIC Educational Resources Information Center

    Debska, Barbara; Guzowska-Swider, Barbara

    2007-01-01

    The article presents the way in which freeware Internet programs can be applied to teach [superscript 1]H NMR spectroscopy. The computer programs described in this article are part of the educational curriculum that explores spectroscopy and spectra interpretation. (Contains 6 figures.)

  19. Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

    NASA Technical Reports Server (NTRS)

    Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

    1989-01-01

    [4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

  20. A stretchable nanowire UV-Vis-NIR photodetector with high performance.

    PubMed

    Yoo, Jewon; Jeong, Sanghwa; Kim, Sungjee; Je, Jung Ho

    2015-03-11

    A simple direct-writing technique can be used to fabricate a stretchable UV-vis-NIR nanowire photodetector (NWPD) consisting of PbS quantum dot (QD)-poly(3-hexylthiopehene) (P3HT) hybrid NWs. The hybrid NWPD shows superior sensitivity and response speed in the UV-vis to NIR range. The stretchable UV-vis-NIR NWPD shows a nearly identical photoresponse under extreme (up to 100%) and repeated (up to 100 cycles) stretching conditions.

  1. (1) H and (13) C NMR data on natural and synthetic capsaicinoids.

    PubMed

    Gómez-Calvario, Víctor; Garduño-Ramírez, María Luisa; León-Rivera, Ismael; Rios, María Yolanda

    2016-04-01

    Capsaicinoids are the compounds responsible for the pungency of chili peppers. These substances have attracted the attention of many research groups in recent decades because of their antinociceptive, analgesic, anti-inflammatory, and anti-obesity properties, among others. There are nearly 160 capsaicinoids reported in the literature. Approximately 25 of them are natural products, while the rest are synthetic or semi-synthetic products. A large amount of NMR data for the capsaicinoids is dispersed throughout literature. Therefore, there is a need to organize all this NMR data in a systematic and orderly way. This review summarizes the (1) H and (13) C NMR data on 159 natural and synthetic capsaicinoids, with a brief discussion of some typical and relevant aspects of these NMR data. Copyright © 2015 John Wiley & Sons, Ltd.

  2. {sup 1}H NMR spectroscopic studies establish that heparanase is a retaining glycosidase

    SciTech Connect

    Wilson, Jennifer C.; Laloo, Andrew Elohim; Singh, Sanjesh; Ferro, Vito

    2014-01-03

    Highlights: •{sup 1}H and {sup 13}C NMR chemical shifts of fondaparinux were fully assigned by 1D and 2D NMR techniques. •Hydrolysis of fondaparinux by heparanase was monitored by {sup 1}H NMR spectroscopy. •Heparanase is established to be a retaining glycosidase. -- Abstract: Heparanase is an endo-β-glucuronidase that cleaves heparan sulfate side chains of proteoglycans in basement membranes and the extracellular matrix (ECM). Heparanase is implicated in several diverse pathological processes associated with ECM degradation such as metastasis, inflammation and angiogenesis and is thus an important target for anti-cancer and anti-inflammatory drug discovery. Heparanase has been classed as belonging to the clan A glycoside hydrolase family 79 based on sequence analysis, secondary structure predictions and mutagenic analysis, and thus it has been inferred that it is a retaining glycosidase. However, there has been no direct experimental evidence to support this conclusion. Herein we describe {sup 1}H NMR spectroscopic studies of the hydrolysis of the pentasaccharide substrate fondaparinux by heparanase, and provide conclusive evidence that heparanase hydrolyses its substrate with retention of configuration and is thus established as a retaining glycosidase. Knowledge of the mechanism of hydrolysis may have implications for future design of inhibitors for this important drug target.

  3. NMR resonance splitting of urea in stretched hydrogels: proton exchange and (1)H/(2)H isotopologues.

    PubMed

    Kuchel, Philip W; Naumann, Christoph; Chapman, Bogdan E; Shishmarev, Dmitry; Håkansson, Pär; Bacskay, George; Hush, Noel S

    2014-10-01

    Urea at ∼12 M in concentrated gelatin gel, that was stretched, gave (1)H and (2)H NMR spectral splitting patterns that varied in a predictable way with changes in the relative proportions of (1)H2O and (2)H2O in the medium. This required consideration of the combinatorics of the two amide groups in urea that have a total of four protonation/deuteration sites giving rise to 16 different isotopologues, if all the atoms were separately identifiable. The rate constant that characterized the exchange of the protons with water was estimated by back-transformation analysis of 2D-EXSY spectra. There was no (1)H NMR spectral evidence that the chiral gelatin medium had caused in-equivalence in the protons bonded to each amide nitrogen atom. The spectral splitting patterns in (1)H and (2)H NMR spectra were accounted for by intra-molecular scalar and dipolar interactions, and quadrupolar interactions with the electric field gradients of the gelatin matrix, respectively.

  4. Identifying metabolites related to nitrogen mineralisation using 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    . T McDonald, Noeleen; Graham, Stewart; Watson, Catherine; Gordon, Alan; Lalor, Stan; Laughlin, Ronnie; Elliott, Chris; . P Wall, David

    2015-04-01

    Exploring new analysis techniques to enhance our knowledge of the various metabolites within our soil systems is imperative. Principally, this knowledge would allow us to link key metabolites with functional influences on critical nutrient processes, such as the nitrogen (N) mineralisation in soils. Currently there are few studies that utilize proton nuclear magnetic resonance spectroscopy (1H NMR) to characterize multiple metabolites within a soil sample. The aim of this research study was to examine the effectiveness of 1H NMR for isolating multiple metabolites that are related to the mineralizable N (MN) capacity across a range of 35 Irish grassland soils. Soils were measured for MN using the standard seven day anaerobic incubation (AI-7). Additionally, soils were also analysed for a range of physio-chemical properties [e.g. total N, total C, mineral N, texture and soil organic matter (SOM)]. Proton NMR analysis was carried on these soils by extracting with 40% methanol:water, lyophilizing and reconstituting in deuterium oxide and recording the NMR spectra on a 400MHz Bruker AVANCE III spectrometer. Once the NMR data were spectrally processed and analysed using multivariate statistical analysis, seven metabolites were identified as having significant relationships with MN (glucose, trimethylamine, glutamic acid, serine, aspartic acid, 4-aminohippuirc acid and citric acid). Following quantification, glucose was shown to explain the largest percentage variability in MN (72%). These outcomes suggest that sources of labile carbon are essential in regulating N mineralisation and the capacity of plant available N derived from SOM-N pools in these soils. Although, smaller in concentration, the amino acids; 4-aminohippuirc acid, glutamic acid and serine also significantly (P<0.05) explained 43%, 27% and 19% of the variability in MN, respectively. This novel study highlights the effectiveness of using 1H NMR as a practical approach to profile multiple metabolites in

  5. Photosensitized Peroxidation of Lipids: An Experiment Using 1H-NMR

    NASA Astrophysics Data System (ADS)

    Smith, Marion W.; Brown, Renee; Smullin, Steven; Eager, Jon

    1997-12-01

    The photoperoxidation of methyl linoleate, using 5,10,15,20-tetraphenyl porphyrin as photosensitizer, was monitored by 60 MHz 1H-NMR. Samples were irradiated for 10-24 hours in front of a 15 W fluorescent light, and NMR signals in the 5-6 ppm and 10-11 ppm region of the spectrum indicated peroxidation products were formed. The absorption of oxygen from the air was measured by attaching the sample tube to a gas burette. When vitamin E was added to the mixture the extent of peroxidation was reduced, showing the protective effect of the antioxidant. These experiments are appropriate for students of biochemistry

  6. (1) H and (13) C NMR characterization of new cycloartane triterpenes from Mangifera indica.

    PubMed

    Escobedo-Martínez, Carolina; Concepción Lozada, M; Hernández-Ortega, Simón; Villarreal, María Luisa; Gnecco, Dino; Enríquez, Raúl G; Reynolds, William

    2012-01-01

    From the stem bark of Mangifera indica, seven cycloartane-type secondary metabolites were isolated. Compound 1 has been isolated for the first time from M. indica, whereas compounds 2 (2a and 2b, as an epimeric mixture), 3, and 4 are new triterpenoid-type cycloartanes. Unambiguous (13) C and (1) H NMR assignments for these compounds and the known compounds mangiferonic acid (compound 5), isomangiferolic acid (compound 6), ambolic acid (compound 7), and friedelin (compound 8) are reported; the latter because full NMR data for these compounds are not available in the literature.

  7. Investigations of La Rioja terroir for wine production using 1H NMR metabolomics.

    PubMed

    López-Rituerto, Eva; Savorani, Francesco; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M; Engelsen, Søren Balling

    2012-04-04

    In this study, La Rioja wine terroir was investigated by the use of (1)H NMR metabolomics on must and wine samples. Rioja is a small wine region in central northern Spain which can geographically be divided into three subareas (Rioja Alta, Rioja Baja, and Rioja Alavesa). The winemaking process from must, through alcoholic and malolactic fermentation, was followed by NMR metabolomics and chemometrics of nine wineries in the Rioja subareas (terroirs). Application of interval extended canonical variate analysis (iECVA) showed discriminative power between wineries which are geographically very close. Isopentanol and isobutanol compounds were found to be key biomarkers for this differentiation.

  8. FTIR, magnetic, 1H NMR spectral and thermal studies of some chelates of caproic acid: Inhibitory effect on different kinds of bacteria

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Korashy, Sabry A.; Kumar, Deo Nandan; Ahmed, Ahmed S.

    2008-06-01

    A convenient method for the preparation of complexes of the Cr 3+, Mn 2+, Fe 3+, Co 2+, Ni 2+, Zn 2+, ZrO 2+, UO 22+, Zr 4+ and Th 4+ ions with caproic acid (Hcap) is reported and this has enabled 10 complexes of caproate anion to be formulated: [Cr(cap) 3]·5H 2O, [Mn(cap) 2(H 2O) 2], [Fe(cap) 3]·12H 2O, [Co(cap) 2(H 2O) 2]·4H 2O, [Ni(cap) 2(H 2O) 2]·3H 2O, [Zn(cap) 2], [ZrO(cap) 2]·3H 2O, [UO 2(cap)(NO 3)], [Zr(cap) 2(Cl) 2] and [Th(cap) 4]. These new complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, 1H NMR and UV-vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. It has been found from the elemental analysis as well as thermal studies that the caproate ligand behaves as bidentate ligand and forming chelates with 1:1 (metal:ligand) stoichiometry for UO 22+, 1:2 for (Mn 2+, Co 2+, Ni 2+, Zn 2+, ZrO 2+ and Zr 4+), 1:3 stoichiometry for (Cr 3+ and Fe 3+) and 1:4 for Th 4+ caproate complexes, respectively, as bidentate chelating. The molar conductance measurements proved that the caproate complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E*, Δ H*, Δ S* and Δ G* are estimated from the DTG curves. The antibacterial activity of the caproic acid and their complexes was evaluated against some gram positive/negative bacteria.

  9. (1)H chemical shift differences of Prelog-Djerassi lactone derivatives: DFT and NMR conformational studies.

    PubMed

    Aímola, Túlio J; Lima, Dimas J P; Dias, Luiz C; Tormena, Cláudio F; Ferreira, Marco A B

    2015-02-21

    This work reports an experimental and theoretical study of the conformational preferences of several Prelog-Djerassi lactone derivatives, to elucidate the (1)H NMR chemical shift differences in the lactonic core that are associated with the relative stereochemistry of these derivatives. The boat-like conformation of explains the anomalous (1)H chemical shift between H-5a and H-5b, in which the two methyl groups (C-8 and C-9) face H-5b, leading to its higher shielding effect.

  10. Evaluation of saffron (Crocus sativus L.) adulteration with plant adulterants by (1)H NMR metabolite fingerprinting.

    PubMed

    Petrakis, Eleftherios A; Cagliani, Laura R; Polissiou, Moschos G; Consonni, Roberto

    2015-04-15

    In the present work, a preliminary study for the detection of adulterated saffron and the identification of the adulterant used by means of (1)H NMR and chemometrics is reported. Authentic Greek saffron and four typical plant-derived materials utilised as bulking agents in saffron, i.e., Crocus sativus stamens, safflower, turmeric, and gardenia were investigated. A two-step approach, relied on the application of both OPLS-DA and O2PLS-DA models to the (1)H NMR data, was adopted to perform authentication and prediction of authentic and adulterated saffron. Taking into account the deficiency of established methodologies to detect saffron adulteration with plant adulterants, the method developed resulted reliable in assessing the type of adulteration and could be viable for dealing with extensive saffron frauds at a minimum level of 20% (w/w).

  11. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology.

  12. Inclusion complex of benzocaine and β-cyclodextrin: 1H NMR and isothermal titration calorimetry studies

    NASA Astrophysics Data System (ADS)

    Mic, Mihaela; Pırnǎu, Adrian; Bogdan, Mircea; Turcu, Ioan

    2013-11-01

    The supramolecular structure of the inclusion complex of β-cyclodextrin with benzocaine in aqueous solution has been investigated by 1H NMR spectroscopy and isothermal titration nanocalorimetry (ITC). Analysis of 1H NMR data by continuous variation method indicates that the benzocaine: β-cyclodextrin inclusion complex occurs and has a 1:1 stoichiometry. Rotating frame NOE spectroscopy (ROESY) was used to ascertain the solution geometry of the host-guest complex which indicates that the benzocaine molecule was included with the aromatic ring into the cyclodextrin cavity. Although the affinity of benzocaine for cyclodextrin is relatively high, the association constant cannot be measured using ITC due to the low solubility of benzocaine in water.

  13. 1H NMR profiling as an approach to differentiate conventionally and organically grown tomatoes.

    PubMed

    Hohmann, Monika; Christoph, Norbert; Wachter, Helmut; Holzgrabe, Ulrike

    2014-08-20

    This study describes the approach of (1)H NMR profiling for the authentication of organically produced tomatoes (Solanum lycopersicum). Overall, 361 tomato samples of two different cultivars and four different producers were regularly analyzed during a 7 month period. The results of principal component analysis showed a significant trend for the separation between organically and conventionally produced tomatoes (p < 0.001 using the t test). Linear discriminant analysis demonstrated good discrimination between the growing regimens, and external validation showed 100% correctly classified tomato samples. Further validation studies, however, also disclosed unexpected differences between individual producers, which interfere with the aim of predicting the cultivation method, yet the results indicate significant differences between (1)H NMR spectra of organically and conventionally grown tomatoes.

  14. (1)H-(13)C NMR-Based Profiling of Biotechnological Starch Utilization.

    PubMed

    Sundekilde, Ulrik K; Meier, Sebastian

    2016-10-04

    Starch is used in food- and nonfood applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized (1)H-(13)C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for downstream process output such as ethanol production from starch. Thus, high-resolution (1)H-(13)C NMR spectroscopic profiles of homooligomeric fragment mixtures in conjunction with chemometric methods provide a useful addition to the analytical chemistry toolbox of biotechnological starch utilization.

  15. Li-S battery analyzed by UV/Vis in operando mode.

    PubMed

    Patel, Manu U M; Demir-Cakan, Rezan; Morcrette, Mathieu; Tarascon, Jean-Marie; Gaberscek, Miran; Dominko, Robert

    2013-07-01

    Battery watch: UV/Vis spectrophotometry is demonstrated as a powerful analytical method for the in situ study of polysulfides. Through the interactions that occur between different chain-length polysulfide molecules and the UV/Vis radiation, quantitative and qualitative determination of the polysulfides formed during Li-S battery operation can be achieved.

  16. Measurement of Ligand–Target Residence Times by 1H Relaxation Dispersion NMR Spectroscopy

    PubMed Central

    2016-01-01

    A ligand-observed 1H NMR relaxation experiment is introduced for measuring the binding kinetics of low-molecular-weight compounds to their biomolecular targets. We show that this approach, which does not require any isotope labeling, is applicable to ligand–target systems involving proteins and nucleic acids of variable molecular size. The experiment is particularly useful for the systematic investigation of low affinity molecules with residence times in the micro- to millisecond time regime. PMID:27933946

  17. Theoretical and experimental investigation of the 1H NMR spectrum of putrescine

    NASA Astrophysics Data System (ADS)

    Allouche, A. R.; Graveron-Demilly, D.; Fauvelle, F.; Aubert-Frécon, M.

    2008-12-01

    Chemical shifts δ and spin-spin coupling constants J have been calculated for the putrescine molecule, a polyamine present in prostate tissue, through a DFT/B3LYP/6-311++G(d,p)/PCM/(GIAO) approach, which has been shown to be accurate in previous work. From δ and J values, calculated for the first time for the isolated and the solvated putrescine, the 1H NMR spectra have been simulated. Comparisons between the calculated and the experimental NMR spectra at 400 MHz show a good agreement and allow to propose reliable values for the NMR spin Hamiltonian parameters of putrescine to be used as good starting values for further quantitation methods of metabolites in prostate tissue.

  18. Detection of Apoptosis and Necrosis in Normal Human Lung Cells Using 1H NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shih, Chwen-Ming; Ko, Wun-Chang; Yang, Liang-Yo; Lin, Chien-Ju; Wu, Jui-Sheng; Lo, Tsui-Yun; Wang, Shwu-Huey; Chen, Chien-Tsu

    2005-05-01

    This study aimed to detect apoptosis and necrosis in MRC-5, a normal human lung cell line, by using noninvasive proton nuclear magnetic resonance (1H NMR). Live MRC-5 cells were processed first for 1H NMR spectroscopy; subsequently their types and the percentage of cell death were assessed on a flow cytometer. Cadmium (Cd) and mercury (Hg) induced apoptosis and necrosis in MRC-5 cells, respectively, as revealed by phosphatidylserine externalization on a flow cytometer. The spectral intensity ratio of methylene (CH2) resonance (at 1.3 ppm) to methyl (CH3) resonance (at 0.9 ppm) was directly proportional to the percentage of apoptosis and strongly and positively correlated with PI staining after Cd treatment (r2 = 0.9868, P < 0.01). In contrast, this ratio only increased slightly within 2-h Hg treatment, and longer Hg exposure failed to produce further increase. Following 2-h Hg exposure, the spectral intensity of choline resonance (at 3.2 ppm) was abolished, but this phenomenon was absent in Cd-induced apoptosis. These findings together demonstrate that 1H NMR is a novel tool with a quantitative potential to distinguish apoptosis from necrosis as early as the onset of cell death in normal human lung cells.

  19. (1)H NMR metabonomic analysis in renal cell carcinoma: a possible diagnostic tool.

    PubMed

    Zira, Athina N; Theocharis, Stamatios E; Mitropoulos, Dionisios; Migdalis, Vasilios; Mikros, Emmanuel

    2010-08-06

    (1)H NMR based metabonomic approach was applied in order to monitor the alterations of plasma metabolic profile in Renal Cell Carcinoma (RCC) patients and controls. (1)H NMR spectra of plasma samples from 32 RCC patients and 13 controls (patients exhibiting benign urologic disease) were recorded and analyzed using multivariate statistical techniques. Alterations in the levels of LDL/VLDL, NAC, lactate, and choline were observed between RCC patients and controls discriminating these groups in Principal Component Analysis (PCA) plots. Post OSC PLS-DA presented a satisfactory clustering between T1 with T3 RCC patients. Decrease in plasma lipid concentrations in RCC patients was verified using conventional clinical chemistry analysis. The results suggest that combination of (1)H NMR spectroscopy with PCA has potential in cancer diagnosis; however, a limitation of the method to monitor RCC is that major biomarkers revealed (lipoproteins and choline) in this metabolic profile are not unique to RCC but may be the result of the presence of any malignancy.

  20. Investigation of 1H NMR chemical shifts of organic dye with hydrogen bonds and ring currents.

    PubMed

    Park, Sung Soo; Won, Yong Sun; Lee, Woojin; Kim, Jae Hong

    2011-04-07

    The (1)H NMR chemical shifts were theoretically computed for the organic dyes 2-(2,6-dimethyl-4H-pyran-4-ylidene)-malononitrile (1), cyano-(2,6-dimethyl-4H-pyran-4-ylidene)-acetic acid methyl ester (2), 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-malononitrile (3), and methyl 2-(2,6-bis(4-(dimethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate (4) at the GIAO/B3LYP/6-311++G(d,p)//B3LYP/6-311++G(d,p) level of theory. Moreover, the intramolecular rotational barriers of the molecules were calculated to evaluate the internal flexibility with respect to the torsional degrees of freedom, and the nuclear-independent chemical shifts (NICS) were employed to analyze the ring currents. The difference was explained in terms of intramolecular hydrogen bonds and ring currents of the molecules. The (1)H NMR spectra were reproduced by experiments for the comparison with computationally constructed data. Our results suggest a good guideline in interpreting (1)H NMR chemical shifts using computational methods and furthermore a reliable perspective for designing molecular structures.

  1. 1H-NMR METABONOMICS ANALYSIS OF SERA DIFFERENTIATES BETWEEN MAMMARY TUMOR-BEARING MICE AND HEALTHY CONTROLS

    EPA Science Inventory

    Global analysis of 1H-NMR spectra of serum is an appealing approach for the rapid detection of cancer. To evaluate the usefulness of this method in distinguishing between mammary tumor-bearing mice and healthy controls, we conducted 1H-NMR metabonomic analyses on serum samples ob...

  2. Translational diffusion in paramagnetic liquids by 1H NMR relaxometry: nitroxide radicals in solution.

    PubMed

    Kruk, D; Korpała, A; Kubica, A; Meier, R; Rössler, E A; Moscicki, J

    2013-01-14

    For nitroxide radicals in solution one can identify three frequency regimes in which (1)H spin-lattice relaxation rate of solvent molecules depend linearly on square root of the (1)H resonance frequency. Combining a recently developed theory of nuclear (proton) spin-lattice relaxation in solutions of nitroxide radicals [D. Kruk et al., J. Chem. Phys. 137, 044512 (2012)] with properties of the spectral density function associated with translational dynamics, relationships between the corresponding linear changes of the relaxation rate (for (14)N spin probes) and relative translational diffusion coefficient of the solvent and solute molecules have been derived (in analogy to (15)N spin probes [E. Belorizky et al., J. Phys. Chem. A 102, 3674 (1998)]). This method allows a simple and straightforward determination of diffusion coefficients in spin-labeled systems, by means of (1)H nuclear magnetic resonance (NMR) relaxometry. The approach has thoroughly been tested by applying to a large set of experimental data-(1)H spin-lattice relaxation dispersion results for solutions of different viscosity (decalin, glycerol, propylene glycol) of (14)N and (15)N spin probes. The experiments have been performed versus temperature (to cover a broad range of translational diffusion coefficients) using field cycling spectrometer which covers three decades in (1)H resonance frequency, 10 kHz-20 MHz. The limitations of NMR relaxometry caused by the time scale of the translational dynamics as well as electron spin relaxation have been discussed. It has been shown that for spin-labeled systems NMR relaxometry gives access to considerably faster diffusion processes than for diamagnetic systems.

  3. Translational diffusion in paramagnetic liquids by 1H NMR relaxometry: Nitroxide radicals in solution

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Korpała, A.; Kubica, A.; Meier, R.; Rössler, E. A.; Moscicki, J.

    2013-01-01

    For nitroxide radicals in solution one can identify three frequency regimes in which 1H spin-lattice relaxation rate of solvent molecules depend linearly on square root of the 1H resonance frequency. Combining a recently developed theory of nuclear (proton) spin-lattice relaxation in solutions of nitroxide radicals [D. Kruk et al., J. Chem. Phys. 137, 044512 (2012)], 10.1063/1.4736854 with properties of the spectral density function associated with translational dynamics, relationships between the corresponding linear changes of the relaxation rate (for 14N spin probes) and relative translational diffusion coefficient of the solvent and solute molecules have been derived (in analogy to 15N spin probes [E. Belorizky et al., J. Phys. Chem. A 102, 3674 (1998)], 10.1021/jp980397h). This method allows a simple and straightforward determination of diffusion coefficients in spin-labeled systems, by means of 1H nuclear magnetic resonance (NMR) relaxometry. The approach has thoroughly been tested by applying to a large set of experimental data—1H spin-lattice relaxation dispersion results for solutions of different viscosity (decalin, glycerol, propylene glycol) of 14N and 15N spin probes. The experiments have been performed versus temperature (to cover a broad range of translational diffusion coefficients) using field cycling spectrometer which covers three decades in 1H resonance frequency, 10 kHz-20 MHz. The limitations of NMR relaxometry caused by the time scale of the translational dynamics as well as electron spin relaxation have been discussed. It has been shown that for spin-labeled systems NMR relaxometry gives access to considerably faster diffusion processes than for diamagnetic systems.

  4. What Is the True Color of Fresh Meat? A Biophysical Undergraduate Laboratory Experiment Investigating the Effects of Ligand Binding on Myoglobin Using Optical, EPR, and NMR Spectroscopy

    ERIC Educational Resources Information Center

    Linenberger, Kimberly; Bretz, Stacey Lowery; Crowder, Michael W.; McCarrick, Robert; Lorigan, Gary A.; Tierney, David L.

    2011-01-01

    With an increased focus on integrated upper-level laboratories, we present an experiment integrating concepts from inorganic, biological, and physical chemistry content areas. Students investigate the effects of ligand strength on the spectroscopic properties of the heme center in myoglobin using UV-vis, [superscript 1]H NMR, and EPR…

  5. Applications of high-resolution 1H solid-state NMR.

    PubMed

    Brown, Steven P

    2012-02-01

    This article reviews the large increase in applications of high-resolution (1)H magic-angle spinning (MAS) solid-state NMR, in particular two-dimensional heteronuclear and homonuclear (double-quantum and spin-diffusion NOESY-like exchange) experiments, in the last five years. These applications benefit from faster MAS frequencies (up to 80 kHz), higher magnetic fields (up to 1 GHz) and pulse sequence developments (e.g., homonuclear decoupling sequences applicable under moderate and fast MAS). (1)H solid-state NMR techniques are shown to provide unique structural insight for a diverse range of systems including pharmaceuticals, self-assembled supramolecular structures and silica-based inorganic-organic materials, such as microporous and mesoporous materials and heterogeneous organometallic catalysts, for which single-crystal diffraction structures cannot be obtained. The power of NMR crystallography approaches that combine experiment with first-principles calculations of NMR parameters (notably using the GIPAW approach) are demonstrated, e.g., to yield quantitative insight into hydrogen-bonding and aromatic CH-π interactions, as well as to generate trial three-dimensional packing arrangements. It is shown how temperature-dependent changes in the (1)H chemical shift, linewidth and DQ-filtered signal intensity can be analysed to determine the thermodynamics and kinetics of molecular level processes, such as the making and breaking of hydrogen bonds, with particular application to proton-conducting materials. Other applications to polymers and biopolymers, inorganic compounds and bioinorganic systems, paramagnetic compounds and proteins are presented. The potential of new technological advances such as DNP methods and new microcoil designs is described.

  6. Identification of fucans from four species of sea cucumber by high temperature 1H NMR

    NASA Astrophysics Data System (ADS)

    Wu, Nian; Chen, Shiguo; Ye, Xingqian; Li, Guoyun; Yin, Li'ang; Xue, Changhu

    2014-10-01

    Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei ( Pg) from Indo-Pacific, Holothuria vagabunda ( Hv) from Norwegian Coast, Stichopus tremulu ( St) from Western Indian Ocean, and Isostichopus badionotu ( Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans (SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer (NMR) and room temperature 13C NMR. The results indicated that Fuc- Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc- Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc- St from the frigid zone and Fuc- Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.

  7. Coating of gold nanoparticles for medical application: UV-VIS

    NASA Astrophysics Data System (ADS)

    Martínez Espinosa, Juan Carlos; Ramírez, Nayem Amtanus Chequer; Funes Oliva, Luis Enrique; Córdova Fraga, Teodoro; Bernal Alvarado, Jesús; Reyes Pablo, Aldelmo; Núñez, Anita Rosa Elvira

    2014-11-01

    The use of nanostructured materials has gained strength in recent years in the biomedical area; new applications such as the detection of components in living cells have been used in pharmaceutical area, specifically to study the interaction of various antitumor drugs in living tissues, the detection of genes that are closely related to some type of cancer, as well as the detections of protein biomarkers for diseases also have been studied in various research laboratories around of the world. In this work, we characterize the variation of the absorbance of gold nanoparticles (GNPs) coated with different concentration of Bovine Serum Albumin (BSA) protein. We use GNPS of 60 nm of the trademark-TED PELLA, the BSA protein trademark of Sigma Aldrich and based on that proposed protocol by Chithrani et al., 2009 with purposes to obtain an alternative model to determine the optimal stability of the nanoparticles coated with the protein. The colloidal solutions were prepared with BSA at different concentrations (0.25, 0.5, 0.75 and 1% M/V), and were centrifuged at 15,000 rpm for 90 minutes (centrifuge Model Z383K) and a constant temperature of 25 °C. All the spectra sets were obtained within the range from 400 to 700 nm using an UV-VIS spectrophotometer (Thermo Scientific Model 51118650). The results showed a R2 of 0.99 for an exponential curve correlation between the concentration of BSA, and the absorbance measured. We found at higher concentrations of BSA, there is a decrease in the intensity of the absorption spectra in the plasmon resonance. This preliminary model obtained can be used in the stabilization of gold nanoparticles with different proteins of biomedical interest in future experiments and support for functionalization of GNPs with specific membrane markers.

  8. (1)H nuclear magnetic resonance (NMR) as a tool to measure dehydration in mice.

    PubMed

    Li, Matthew; Vassiliou, Christophoros C; Colucci, Lina A; Cima, Michael J

    2015-08-01

    Dehydration is a prevalent pathology, where loss of bodily water can result in variable symptoms. Symptoms can range from simple thirst to dire scenarios involving loss of consciousness. Clinical methods exist that assess dehydration from qualitative weight changes to more quantitative osmolality measurements. These methods are imprecise, invasive, and/or easily confounded, despite being practiced clinically. We investigate a non-invasive, non-imaging (1)H NMR method of assessing dehydration that attempts to address issues with existing clinical methods. Dehydration was achieved by exposing mice (n = 16) to a thermally elevated environment (37 °C) for up to 7.5 h (0.11-13% weight loss). Whole body NMR measurements were made using a Bruker LF50 BCA-Analyzer before and after dehydration. Physical lean tissue, adipose, and free water compartment approximations had NMR values extracted from relaxation data through a multi-exponential fitting method. Changes in before/after NMR values were compared with clinically practiced metrics of weight loss (percent dehydration) as well as blood and urine osmolality. A linear correlation between tissue relaxometry and both animal percent dehydration and urine osmolality was observed in lean tissue, but not adipose or free fluids. Calculated R(2) values for percent dehydration were 0.8619 (lean, P < 0.0001), 0.5609 (adipose, P = 0.0008), and 0.0644 (free fluids, P = 0.3445). R(2) values for urine osmolality were 0.7760 (lean, P < 0.0001), 0.5005 (adipose, P = 0.0022), and 0.0568 (free fluids, P = 0.3739). These results suggest that non-imaging (1)H NMR methods are capable of non-invasively assessing dehydration in live animals.

  9. Metabolomic Investigations of American Oysters Using 1H-NMR Spectroscopy

    PubMed Central

    Tikunov, Andrey P.; Johnson, Christopher B.; Lee, Haakil; Stoskopf, Michael K.; Macdonald, Jeffrey M.

    2010-01-01

    The Eastern oyster (Crassostrea virginica) is a useful, robust model marine organism for tissue metabolism studies. Its relatively few organs are easily delineated and there is sufficient understanding of their functions based on classical assays to support interpretation of advanced spectroscopic approaches. Here we apply high-resolution proton nuclear magnetic resonance (1H NMR)-based metabolomic analysis to C. virginica to investigate the differences in the metabolic profile of different organ groups, and magnetic resonance imaging (MRI) to non-invasively identify the well separated organs. Metabolites were identified in perchloric acid extracts of three portions of the oyster containing: (1) adductor muscle, (2) stomach and digestive gland, and (3) mantle and gills. Osmolytes dominated the metabolome in all three organ blocks with decreasing concentration as follows: betaine > taurine > proline > glycine > ß-alanine > hypotaurine. Mitochondrial metabolism appeared most pronounced in the adductor muscle with elevated levels of carnitine facilitating ß-oxidation, and ATP, and phosphoarginine synthesis, while glycogen was elevated in the mantle/gills and stomach/digestive gland. A biochemical schematic is presented that relates metabolites to biochemical pathways correlated with physiological organ functions. This study identifies metabolites and corresponding 1H NMR peak assignments for future NMR-based metabolomic studies in oysters. PMID:21116407

  10. Magic angle spinning NMR of proteins: high-frequency dynamic nuclear polarization and (1)H detection.

    PubMed

    Su, Yongchao; Andreas, Loren; Griffin, Robert G

    2015-01-01

    Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.

  11. 1H to 13C Energy Transfer in Solid State NMR Spectroscopy of Natural Organic Systems

    NASA Astrophysics Data System (ADS)

    Berns, Anne E.; Conte, Pellegrino

    2010-05-01

    Cross polarization (CP) magic angle spinning (MAS) 13C-NMR spectroscopy is a solid state NMR technique widely used to study chemical composition of organic materials with low or no solubility in the common deuterated solvents used to run liquid state NMR experiments. Based on the magnetization transfer from abundant nuclei (with spin of 1 -2) having a high gyromagnetic ratio (γ), such as protons, to the less abundant 13C nuclei with low γ values, 13C-CPMAS NMR spectroscopy is often applied in environmental chemistry to obtain quantitative information on the chemical composition of natural organic matter (NOM) (Conte et al., 2004), although its quantitative assessment is still matter of heavy debates. Many authors (Baldock et al., 1997; Conte et al., 1997, 2002; Dria et al., 2002; Kiem et al., 2000; Kögel-Knabner, 2000; Preston, 2001), reported that the application of appropriate instrument setup as well as the use of special pulse sequences and correct spectra elaboration may provide signal intensities that are directly proportional to the amount of nuclei creating a NMR signal. However, many other papers dealt with the quantitative unsuitability of 13C-CPMAS NMR spectroscopy. Among those, Mao et al. (2000), Smernik and Oades (2000 a,b), and Preston (2001) reported that cross-polarized NMR techniques may fail in a complete excitation of the 13C nuclei. In fact, the amount of observable carbons via 13C-CPMAS NMR spectroscopy appeared, in many cases, lower than that measured by a direct observation of the 13C nuclei. As a consequence, cross-polarized NMR techniques may provide spectra where signal distribution may not be representative of the quantitative distribution of the different natural organic matter components. Cross-polarization is obtained after application of an initial 90° x pulse on protons and a further spin lock pulse (along the y axis) having a fixed length (contact time) for both nuclei (1H and 13C) once the Hartmann-Hahn condition is matched

  12. [Study on three different species tibetan medicine sea buckthorn by 1H-NMR-based metabonomics].

    PubMed

    Su, Yong-Wen; Tan, Er; Zhang, Jing; You, Jia-Li; Liu, Yue; Liu, Chuan; Zhou, Xiang-Dong; Zhang, Yi

    2014-11-01

    The 1H-NMR fingerprints of three different species tibetan medicine sea buckthorn were established by 1H-HMR metabolomics to find out different motablism which could provide a new method for the quality evaluation of sea buckthorn. The obtained free induction decay (FID) signal will be imported into MestReNova software and into divide segments. The data will be normalized and processed by principal component analysis and.partial least squares discriminant analysis to perform pattern recognition. The results showed that 25 metabolites belonging to different chemical types were detected from sea buckthorn,including flavonoids, triterpenoids, amino acids, carbohydrates, fatty acids, etc. PCA and PLS-DA analysis showed three different varietiest of sea buckthorn that can be clearly separated by the content of L-quebrachitol, malic acid and some unidentified sugars, which can be used as the differences metabolites of three species of sea buckthorn. 1H-NMR-based metabonomies method had a holistic characteristic with sample preparation and handling. The results of this study can offer an important reference for the species identification and quality control of sea buckthorn.

  13. Nanoliter-volume 1H NMR detection using periodic stopped-flow capillary electrophoresis.

    PubMed

    Olson, D L; Lacey, M E; Webb, A G; Sweedler, J V

    1999-08-01

    Recent advances in the analysis of nanoliter volumes using 1H NMR microcoils have led to the application of microcoils as detectors for capillary electrophoresis (CE). Custom NMR probes consisting of 1-mm-long solenoidal microcoils are fabricated from 50-micron diameter wire wrapped around capillaries to create nanoliter-volume detection cells. For geometries in which the capillary and static magnetic field are not parallel, the electrophoretic current induces a magnetic field gradient which degrades the spectroscopic information obtainable from CE/NMR. To reduce this effect and allow longer analyte observation times, the electrophoretic voltage is periodically interrupted so that 1-min high-resolution NMR spectra are obtained for every 15 s of applied voltage. The limits of detection (LODs; based on S/N = 3) for CE/NMR for arginine are 57 ng (330 pmol; 31 mM) and for triethylamine (TEA) are 9 ng (88 pmol; 11 mM). Field-amplified stacking is used for sample preconcentration. As one example, a 290-nL injection of a mixture of arginine and TEA both at 50 mM (15 nmol of each injected) is stacked severalfold for improved concentration LODs while achieving a separation efficiency greater than 50,000. Dissolving a sample in a mixture of 10% H2O/90% D2O allows H2O to serve as the nearly ideal neutral tracer and allows direct observation of the parabolic and flat flow profiles associated with gravimetric and electrokinetic injection, respectively. The unique capabilities of CE and the rich spectral information provided by NMR spectroscopy combine to yield a valuable analytical tool, especially in the study of mass-limited samples.

  14. Survey and qualification of internal standards for quantification by 1H NMR spectroscopy.

    PubMed

    Rundlöf, Torgny; Mathiasson, Marie; Bekiroglu, Somer; Hakkarainen, Birgit; Bowden, Tim; Arvidsson, Torbjörn

    2010-09-05

    In quantitative NMR (qNMR) selection of an appropriate internal standard proves to be crucial. In this study, 25 candidate compounds considered to be potent internal standards were investigated with respect to the ability of providing unique signal chemical shifts, purity, solubility, and ease of use. The (1)H chemical shift (delta) values, assignments, multiplicities and number of protons (for each signal), appropriateness (as to be used as internal standards) in four different deuterated solvents (D(2)O, DMSO-d(6), CD(3)OD, CDCl(3)) were studied. Taking into account the properties of these 25 internal standards, the most versatile eight compounds (2,4,6-triiodophenol, 1,3,5-trichloro-2-nitrobenzene, 3,4,5-trichloropyridine, dimethyl terephthalate, 1,4-dinitrobenzene, 2,3,5-triiodobenzoic acid, maleic acid and fumaric acid) were qualified using both differential scanning calorimetry (DSC) and NMR spectroscopy employing highly pure acetanilide as the reference standard. The data from these two methods were compared as well as utilized in the quality assessment of the compounds as internal standards. Finally, the selected internal standards were tested and evaluated in a real case of quantitative NMR analysis of a paracetamol pharmaceutical product.

  15. Automatic 1H-NMR Screening of Fatty Acid Composition in Edible Oils

    PubMed Central

    Castejón, David; Fricke, Pascal; Cambero, María Isabel; Herrera, Antonio

    2016-01-01

    In this work, we introduce an NMR-based screening method for the fatty acid composition analysis of edible oils. We describe the evaluation and optimization needed for the automated analysis of vegetable oils by low-field NMR to obtain the fatty acid composition (FAC). To achieve this, two scripts, which automatically analyze and interpret the spectral data, were developed. The objective of this work was to drive forward the automated analysis of the FAC by NMR. Due to the fact that this protocol can be carried out at low field and that the complete process from sample preparation to printing the report only takes about 3 min, this approach is promising to become a fundamental technique for high-throughput screening. To demonstrate the applicability of this method, the fatty acid composition of extra virgin olive oils from various Spanish olive varieties (arbequina, cornicabra, hojiblanca, manzanilla, and picual) was determined by 1H-NMR spectroscopy according to this protocol. PMID:26891323

  16. UV-cured polymeric films containing ZnO and silver nanoparticles with UV-vis light-assisted photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Podasca, Viorica E.; Buruiana, Tinca; Buruiana, Emil C.

    2016-07-01

    Hybrid polymer composites incorporating preformed ZnO alone or its mixture with Ag nanoparticles created during UV irradiation of some urethane acrylic monomers including trietoxysilylpropyl carbamoyloxyethyl methacrylate were synthesized and characterized by spectroscopic (1H (13C) NMR, FTIR, UV-vis, fluorescence, X-ray diffraction) and microscopic (AFM, ESEM/EDX, TEM) techniques. The results confirmed that the double bond conversion measured through FTIR spectroscopy varied in the range of 57-90% (after 60 s of irradiation), exhibiting formulation composition dependence. In the crosslinked polymer networks the existence of individual nanoparticles with primarily spherical shape and sizes between 5 and 15 nm for ZnO, and around 3 nm for in situ photogenerated silver nanoparticles was evidenced. Additionally, the photocatalytic effect of the photopolymerized hybrid films was investigated by determining the decomposition rate of the methylene blue (MB) in ethanol (over 90%) under UV (2.7 × 10-2 s-1) and visible irradiation (2.9 × 10-2 min-1). It was found that the composite films containing a higher amount of ZnO-Ag nanoparticles placed in water induced the photodecomposition of MB (∼87% after 100 min of visible irradiation; k = 2.1 × 10-2 min-1). The good efficiency of the NPs from these polymer films make them attractive for applications in photocatalysis of organic dye molecules.

  17. Assessing Heterogeneity of Osteolytic Lesions in Multiple Myeloma by 1H HR-MAS NMR Metabolomics

    PubMed Central

    Tavel, Laurette; Fontana, Francesca; Garcia Manteiga, Josè Manuel; Mari, Silvia; Mariani, Elisabetta; Caneva, Enrico; Sitia, Roberto; Camnasio, Francesco; Marcatti, Magda; Cenci, Simone; Musco, Giovanna

    2016-01-01

    Multiple myeloma (MM) is a malignancy of plasma cells characterized by multifocal osteolytic bone lesions. Macroscopic and genetic heterogeneity has been documented within MM lesions. Understanding the bases of such heterogeneity may unveil relevant features of MM pathobiology. To this aim, we deployed unbiased 1H high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) metabolomics to analyze multiple biopsy specimens of osteolytic lesions from one case of pathological fracture caused by MM. Multivariate analyses on normalized metabolite peak integrals allowed clusterization of samples in accordance with a posteriori histological findings. We investigated the relationship between morphological and NMR features by merging morphological data and metabolite profiling into a single correlation matrix. Data-merging addressed tissue heterogeneity, and greatly facilitated the mapping of lesions and nearby healthy tissues. Our proof-of-principle study reveals integrated metabolomics and histomorphology as a promising approach for the targeted study of osteolytic lesions. PMID:27809247

  18. 1H-NMR-based metabolomic study on toxicity of methomyl and methidathion in fish.

    PubMed

    Yoon, Dahye; Kim, Siwon; Lee, Minji; Yoon, Changshin; Kim, Suhkmann

    2016-12-01

    A (1)H-nuclear magnetic resonance (NMR) spectroscopy with multivariate analysis was applied to detect the toxicity of antiacetylcholinesterase insecticides, methomyl (methyl (1E)-N-(methylcarbamoyloxy)ethanimidothioate) and methidathion (3-(dimethoxyphosphinothioyl sulfanylmethyl)-5-methoxy-1,3,4-thiadiazol-2-one), using zebrafish (Danio rerio) and Chinese bleak (Aphyocypris chinensis). Generally, methomyl and methidathion have been believed not to highly accumulate in fish tissues. However, these pesticides showed their toxicity by altering patterns of whole-body metabolites in neurotransmitter balance, energy metabolism, oxidative stress, and muscle maintenance in low concentrations. We used Pearson correlation analysis to contextualize the metabolic markers in pesticide treated groups. We observed that the positive correlations of choline with acetate and betaine in untreated control were shifted to null correlations showing acetylcholinesterase specific toxicity. This research demonstrated the applicability and potential of NMR metabolomics in detecting toxic effects of insecticide with a modicum of concentrations in aquatic environment.

  19. Experimental and calculated 1H, 13C, 15N NMR spectra of famotidine

    NASA Astrophysics Data System (ADS)

    Barańska, M.; Czarniecki, K.; Proniewicz, L. M.

    2001-05-01

    Famotidine, 3-[[[2-[(aminoiminomethyl)amino]-4-thiazolyl]methyl]thio]- N-(aminosulfonyl), is a histamine H 2-receptor blocker that has been used mainly for the treatment of peptic ulcers and the Zollinger-Ellison syndrome. Its NMR spectra in different solvents were reported earlier; however, detailed interpretation has not been done thus far. In this work, experimental 1H, 13C and 15N NMR spectra of famotidine dissolved in DMSO-d 6 are shown. The assignment of observed chemical shifts is based on quantum chemical calculation at the Hartree-Fock/6-31G ∗ level. The geometry optimization of the famotidine molecule with two internal hydrogen bonds, i.e. [N(3)-H(23)⋯N(9) and N(3)⋯H(34)-N(20)], is done by using the B3LYP method with the 6-31G ∗ basis set.

  20. Structural analysis of complex saponins of Balanites aegyptiaca by 800 MHz 1H NMR spectroscopy.

    PubMed

    Staerk, Dan; Chapagain, Bishnu P; Lindin, Therese; Wiesman, Zeev; Jaroszewski, Jerzy W

    2006-10-01

    The main saponin (1) present in the mesocarp of Balanites aegyptiaca fruit is a mixture of 22R and 22S epimers of 26-(O-beta-D-glucopyranosyl)-3-beta-[4-O-(beta-D-glucopyranosyl)-2-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyloxy]-22,26-dihydroxyfurost-5-ene. This structure differs from a previously reported saponin isolated from this source by the site of attachment of the rhamnosyl residue, and presumably represents a structural revision of the latter. The main saponin (2) present in the kernel is a xylopyranosyl derivative of 1. The use of high-field NMR enabled the practically complete assignment of 1H and 13C chemical shifts of these complex saponins, existing as a mixture of C-22 epimers. Moreover, the work represents a new approach to structural elucidation of saponins: direct preparative-scale HPLC-RID of crude extracts followed by high-field NMR investigations supported by ESI-MSn.

  1. 1H, 13C and 15N NMR assignments of phenazopyridine derivatives.

    PubMed

    Burgueño-Tapia, Eleuterio; Mora-Pérez, Yolanda; Morales-Ríos, Martha S; Joseph-Nathan, Pedro

    2005-03-01

    Phenazopyridine hydrochloride (1), a drug in clinical use for many decades, and some derivatives were studied by one- and two-dimensional (1)H, (13)C and (15)N NMR methodology. The assignments, combined with DFT calculations, reveal that the preferred protonation site of the drug is the pyridine ring nitrogen atom. The chemoselective acetylation of phenazopyridine (2) and its influence on the polarization of the azo nitrogen atoms were evidenced by the (15)N NMR spectra. Molecular calculations of the phenazopyridines 2-4 show that the pyridine and phenyl groups are oriented in an antiperiplanar conformation with intramolecular hydrogen bonding between the N-b atom and the C-2 amino group preserving the E-azo stereochemistry.

  2. The application of BTEM to UV-vis and UV-vis CD spectroscopies: the reaction of Rh4(CO)12 with chiral and achiral ligands.

    PubMed

    Cheng, Shuying; Gao, Feng; Krummel, Karl I; Garland, Marc

    2008-02-15

    Two different organometallic ligand substitution reactions were investigated: (1) an achiral reactive system consisting of Rh(4)(CO)(12)+PPh(3)right harpoon over left harpoonRh(4)(CO)(11)PPh(3)+CO in n-hexane under argon; and (2) a chiral reactive system consisting of Rh(4)(CO)(12)+(S)-BINAPright harpoon over left harpoonRh(4)(CO)(10)BINAP+2CO in cyclohexane under argon. These two reactions were run at ultra high dilution. In both multi-component reactive systems the concentrations of all the solutes were less than 40ppm and many solute concentrations were just 1-10ppm. In situ spectroscopic measurements were carried out using UV-vis (Ultraviolet-visible) spectroscopy and UV-vis CD spectroscopy on the reactive organometallic systems (1) and (2), respectively. The BTEM algorithm was applied to these spectroscopic data sets. The reconstructed UV-vis pure component spectra of Rh(4)(CO)(12), Rh(4)(CO)(11)PPh(3) and Rh(4)(CO)(10)BINAP as well as the reconstructed UV-vis CD pure component spectra of Rh(4)(CO)(10)BINAP were successfully obtained from BTEM analyses. All these reconstructed pure component spectra are in good agreement with the experimental reference spectra. The concentration profiles of the present species were obtained by performing a least square fit with mass balance constraints for the reactions (1) and (2). The present results indicate that UV-vis and UV-vis-CD spectroscopies can be successfully combined with an appropriate chemometric technique in order to monitor reactive organometallic systems having UV and Vis chromophores.

  3. [1H-NMR studies of the ACTH-like immunoregulatory peptides].

    PubMed

    Khristoforov, V S; Kutyshenko, V P; Abramov, V M; Zav'ialov, V P

    1997-01-01

    A comparative study of the conformational and dynamics properties of the ACTH-like linear peptides, sequences of which correspond to amino acid residues 11-20 of the heavy chain of human immunoglobulin G1 Eu, residues 78-85 of human pro-interleukin-1 alpha and site 10-18 of human ACTH, was performed in aqueous solution and dimethylsulfoxide by 1H-NMR spectroscopy at 400 MHz. The peptides were shown to possess an unordered unfolded flexible conformation in aqueous solution. The revealed structural and dynamic features of the peptides are discussed together with biological activity of this class of compounds.

  4. 1H NMR investigation of self-association of vanillin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bogdan, Mircea; Floare, Calin G.; Pîrnau, Adrian

    2009-08-01

    A self-association of vanillin have been studied by 1H NMR spectroscopy using the analysis of proton chemical shifts changes in aqueous solution as a function of concentration. The experimental results have been analysed using indefinite non-cooperative and cooperative models of molecular self-association, enabling the determination of equilibrium constants, parameters of cooperativity and the limiting values of vanillin proton chemical shifts in the complex. It was found that the dimer formation creates energetically favourable conditions for subsequent molecular association.

  5. High-resolution /sup 1/H NMR study of the solution structure of alamethicin

    SciTech Connect

    Esposito, G.; Carver, J.A.; Boyd, J.; Campbell, I.D.

    1987-02-24

    A /sup 1/H NMR study of the peptide alamethicin, which forms voltage-gated ion channels in membranes, is described. The molecule was studied in methanol as a function of temperature and pH. A complete assignment of the spectra is given, including several stereospecific assignments. Alamethicin was found to have a structure substantially similar to the crystal although, in solution, the C-terminal dipeptide adopts a somewhat extended conformation. The overall conformation was insensitive to the ionization of the side chain of the ionizable group, Glu-18.

  6. Structure determination of noncanonical RNA motifs guided by 1H NMR chemical shifts

    PubMed Central

    Sripakdeevong, Parin; Cevec, Mirko; Chang, Andrew T.; Erat, Michèle C.; Ziegeler, Melanie; Zhao, Qin; Fox, George E.; Gao, Xiaolian; Kennedy, Scott D.; Kierzek, Ryszard; Nikonowicz, Edward P.; Schwalbe, Harald; Sigel, Roland K. O.; Turner, Douglas H.; Das, Rhiju

    2014-01-01

    Structured non-coding RNAs underline fundamental cellular processes, but determining their 3D structures remains challenging. We demonstrate herein that integrating NMR 1H chemical shift data with Rosetta de novo modeling can consistently return high-resolution RNA structures. On a benchmark set of 23 noncanonical RNA motifs, including 11 blind targets, Chemical-Shift-ROSETTA for RNA (CS-ROSETTA-RNA) recovered the experimental structures with high accuracy (0.6 to 2.0 Å all-heavy-atom rmsd) in 18 cases. PMID:24584194

  7. 1H and 13C NMR study on some substituted azolidine derivatives

    NASA Astrophysics Data System (ADS)

    Cerioni, Giovanni; Cristiani, Franco; Devillanova, Francesco A.; Diaz, Angelo; Verani, Gaetano

    The 1H and 13C NMR spectra carried out on R overlineN·CH 2·CH 2·X·C O (where for R = H, X = NH, NMe, NEt, CH 2, S, O; for R = Me, X = NMe, CH 2; for R = Et, X = NEt) are reported. The comparison of these results with those obtained for the thionic and selonic isologues shows that sulphur and selenium have a greater deshielding effect on the ring than oxygen. The resonance of the carbons not involved in the π system have been correlated with the σ charges calculated by the DEL RE method.

  8. 1H NMR spectral studies on the polymerization mechanism of indole and its derivatives

    NASA Astrophysics Data System (ADS)

    Xu, Jingkun; Hou, Jian; Zhou, Weiqiang; Nie, Guangming; Pu, Shouzhi; Zhang, Shusheng

    2006-03-01

    The existence of N sbnd H bond according to the hydrogen nuclear magnetic resonance ( 1H NMR) spectra of polyindole and its derivatives, such as poly(5-bromoindole), poly(5-cyanoindole), poly(5-nitroindole), poly(5-methylindole), proved polymerization of high-quality polyindoles, which were electrosynthesized from middle strong Lewis acid boron trifluoride diethyl etherate (BFEE) and its mixed electrolytes with additional diethyl ether, occurred at 2,3-position. The elongation of the conjugation length made the chemical shift of all the protons of polyindoles to lower field in comparison with those of monomers.

  9. Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

    DOE PAGES

    Alam, Todd M.; Liao, Zuolei; Nyman, May; ...

    2016-04-27

    Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules andmore » of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

  10. 1H NMR studies of ligand and H/D exchange reactions of cis- and trans-([14]aneN4)(H2O)RhH2+ in aqueous solutions.

    PubMed

    Lemma, Kelemu; Ellern, Arkady; Bakac, Andreja

    2003-06-02

    Substitution and exchange reactions of cis- and trans-L(1)(H(2)O)RhH(2+) (L(1) = 1,4,8,11-tetraazacyclotetradecane = [14]aneN(4)) were studied in aqueous solutions by UV-vis and (1)H NMR spectroscopies. At pH 1 and 25 degrees C, the substitution of SCN(-) for the coordinated molecule of water is rapid and thermodynamically favorable. Spectrophotometric determinations yielded the equilibrium constants K = 1.49 x 10(3) M(-1) (cis) and 1.44 x 10(3) (trans). (1)H NMR studies in D(2)O revealed a rapid dynamic process, interpreted as the exchange between coordinated water and X(-) (X = Cl, Br, or I). On the other hand, no line broadening was observed for the strongly bound ligands CN(-) and SCN(-). The complex trans-L(1)(D(2)O)RhH(2+) undergoes a base-catalyzed H/D exchange of the hydride in D(2)O with a rate constant of (1.45 +/- 0.02) x 10(3) M(-1) s(-1). The exchange in the cis isomer is very slow under similar conditions. The complex cis-[L(1)ClRhH](ClO(4)) crystallizes in the centrosymmetric Ponemacr; space group, unit cell dimensions a = 8.9805(11) A, b = 9.1598(11) A, c = 10.4081(13) A, alpha = 81.091(2) degrees, beta = 81.978(2) degrees, gamma = 88.850(2) degrees. The rhodium atom resides in a slightly distorted octahedral environment consisting of the four N atoms of the cyclam, a stereochemically active hydrogen, and a chlorine atom.

  11. Water Solvent Effect on Theoretical Evaluation of (1)H NMR Chemical Shifts: o-Methyl-Inositol Isomer.

    PubMed

    Dos Santos, Hélio F; Chagas, Marcelo A; De Souza, Leonardo A; Rocha, Willian R; De Almeida, Mauro V; Anconi, Cleber P A; De Almeida, Wagner B

    2017-04-13

    In this paper, density functional theory calculations of nuclear magnetic resonance (NMR) chemical shifts for l-quebrachitol isomer, previously studied in our group, are reported with the aim of investigating in more detail the water solvent effect on the prediction of (1)H NMR spectra. In order to include explicit water molecules, 20 water-l-quebrachitol configurations obtained from Monte Carlo simulation were selected to perform geometry optimizations using the effective fragment potential method encompassing 60 water molecules around the solute. The solvated solute optimized geometries were then used in B3LYP/6-311+G(2d,p) NMR calculations with PCM-water. The inclusion of explicit solvent in the B3LYP NMR calculations resulted in large changes in the (1)H NMR profiles. We found a remarkable improvement in the agreement with experimental NMR profiles when the explicit hydrated l-quebrachitol structure is used in B3LYP (1)H NMR calculations, yielding a mean absolute error (MAE) of only 0.07 ppm, much lower than reported previously for the gas phase optimized structure (MAE = 0.11 ppm). In addition, a very improved match between theoretical and experimental (1)H NMR spectrum measured in D2O was achieved with the new hydrated optimized l-quebrachitol structure, showing that a fine-tuning of the theoretical NMR spectra can be accomplished once solvent effects are properly considered.

  12. 1H and 13C resonance designation of antimycin A1 by two-dimensional NMR spectroscopy

    USGS Publications Warehouse

    Abidi, S.L.; Adams, B.R.

    1987-01-01

    Complete 1H and 13C resonance assignments of antimycin A1 were accomplished by two-dimensional NMR techniques, viz. 1H homonuclear COSY correlation, heteronuclear 13C-1H chemical shift correlation and long-range heteronuclear 13C-1H COLOC correlation. Antimycin A1 was found to consist of two isomeric components in a 2:1 ratio based on NMR spectroscopic evidence. The structure of the major component was newly assigned as the 8-isopentanoic acid ester. The spectra of the minor component were consistent with the known structure of antimycin A1.

  13. Low resolution 1H NMR assignment of proton populations in pound cake and its polymeric ingredients.

    PubMed

    Luyts, A; Wilderjans, E; Waterschoot, J; Van Haesendonck, I; Brijs, K; Courtin, C M; Hills, B; Delcour, J A

    2013-08-15

    Based on a model system approach, five different proton populations were distinguished in pound cake crumb using one dimensional low resolution (1)H NMR spectroscopy. In free induction decay (FID) measurements, proton populations were assigned to (i) non-exchanging CH protons of crystalline starch, proteins and crystalline fat and (ii) non-exchanging CH protons of amorphous starch and gluten, which are in little contact with water. In Carr-Purcell-Meiboom-Gill (CPMG) measurements, three proton populations were distinguished. The CPMG population with the lowest mobility and the FID population with the highest mobility represent the same proton population. The two CPMG proton populations with the highest mobility were assigned to exchanging protons (i.e., protons of water, starch, gluten, egg proteins and sugar) and protons of lipids (i.e., protons of egg yolk lipids and amorphous lipid fraction of margarine) respectively. Based on their spin-lattice relaxation times (T1), two dimensional (1)H NMR spectroscopy further resolved the two proton populations with the highest mobility into three and two proton populations, respectively.

  14. (1)H-NMR-based metabolomic studies of bisphenol A in zebrafish (Danio rerio).

    PubMed

    Yoon, Changshin; Yoon, Dahye; Cho, Junghee; Kim, Siwon; Lee, Heonho; Choi, Hyeonsoo; Kim, Suhkmann

    2017-04-03

    Proton nuclear magnetic resonance ((1)H-NMR) spectroscopy was used to study the response of zebrafish (Danio rerio) to increasing concentrations of bisphenol A (4,4'-(propane-2,2-diyl)diphenol, BPA). Orthogonal partial least squares discriminant analysis (OPLS-DA) was applied to detect aberrant metabolomic profiles after 72 h of BPA exposure at all levels tested (0.01, 0.1, and 1.0 mg/L). The OPLS-DA score plots showed that BPA exposure caused significant alterations in the metabolome. The metabolomic changes in response to BPA exposure generally exhibited nonlinear patterns, with the exception of reduced levels of several metabolites, including glutamine, inosine, lactate, and succinate. As the level of BPA exposure increased, individual metabolite patterns indicated that the zebrafish metabolome was subjected to severe oxidative stress. Interestingly, ATP levels increased significantly at all levels of BPA exposure. In the present study, we demonstrated the applicability of (1)H-NMR-based metabolomics to identify the discrete nature of metabolic changes.

  15. The molecular structure and vibrational, (1)H and (13)C NMR spectra of lidocaine hydrochloride monohydrate.

    PubMed

    Badawi, Hassan M; Förner, Wolfgang; Ali, Shaikh A

    2016-01-05

    The structure, vibrational and NMR spectra of the local anesthetic drug lidocaine hydrochloride monohydrate salt were investigated by B3LYP/6-311G(∗∗) calculations. The lidocaine·HCl·H2O salt is predicted to have the gauche structure as the predominant form at ambient temperature with NCCN and CNCC torsional angles of 110° and -123° as compared to 10° and -64°, respectively in the base lidocaine. The repulsive interaction between the two N-H bonds destabilized the gauche structure of lidocaine·HCl·H2O salt. The analysis of the observed vibrational spectra is consistent with the presence of the lidocaine salt in only one gauche conformation at room temperature. The (1)H and (13)C NMR spectra of lidocaine·HCl·H2O were interpreted by experimental and DFT calculated chemical shifts of the lidocaine salt. The RMSD between experimental and theoretical (1)H and (13)C chemical shifts for lidocaine·HCl·H2O is 2.32 and 8.21ppm, respectively.

  16. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy.

    PubMed

    Jakes, W; Gerdova, A; Defernez, M; Watson, A D; McCallum, C; Limer, E; Colquhoun, I J; Williamson, D C; Kemsley, E K

    2015-05-15

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz (1)H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional "authentic" beef region (p=0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze-thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz (1)H NMR represents a feasible high-throughput approach for screening raw meat.

  17. Toxicity assessment of Arisaematis Rhizoma in rats by a (1)H NMR-based metabolomics approach.

    PubMed

    Dong, Ge; Wang, Junsong; Guo, Pingping; Wei, Dandan; Yang, Minghua; Kong, Lingyi

    2015-02-01

    Arisaematis Rhizoma (AR), a famous traditional Chinese medicine, has been widely used in Asia over thousands of years. Documented with noticeable toxicity in ancient books, AR has been used to treat various diseases in the clinic. Therefore, it is important to assess the toxicity of AR dynamically and holistically. In this study, a (1)H NMR-based metabolomics approach complemented with serum chemistry and histopathology has been applied to investigate the toxicity of AR. Rats were intragastrically administered with AR (0, 0.5 and 1 g kg(-1) body weight) for 30 days, and serum and urine samples were collected. Their (1)H NMR profiles were analyzed by multivariate pattern recognition techniques to denote metabolic variations induced by AR, and 13 metabolites in urine and 6 metabolites in serum were significantly altered, which suggested that disturbances in energy metabolism, perturbation of the gut microflora environment, membrane damage, folate deficiency and injury of kidneys are produced by AR. Histopathology showed a slight vacuolization of the glomerular matrix and edema of renal tubular epithelial cells in kidneys of AR administered rats, which were evidenced by increased levels of blood urea nitrogen and creatinine in serum chemistry. Our results indicated that oral administration of crude AR was found to induce slight renal toxicity. Therefore, precautions should be made to monitor the potential nephrotoxicity of AR in clinical use. The metabolomics approach provided a promising tool for the study and better understanding of TCM-induced toxicity dynamically and holistically.

  18. UV-visible and (1)H-(15)N NMR spectroscopic studies of colorimetric thiosemicarbazide anion sensors.

    PubMed

    Farrugia, Kristina N; Makuc, Damjan; Podborska, Agnieszka; Szaciłowski, Konrad; Plavec, Janez; Magri, David C

    2015-02-14

    Four model thiosemicarbazide anion chemosensors containing three N-H bonds, substituted with phenyl and/or 4-nitrophenyl units, were synthesised and studied for their anion binding abilities with hydroxide, fluoride, acetate, dihydrogen phosphate and chloride. The anion binding properties were studied in DMSO and 9 : 1 DMSO-H2O by UV-visible absorption and (1)H/(13)C/(15)N NMR spectroscopic techniques and corroborated with DFT studies. Significant changes were observed in the UV-visible absorption spectra with all anions, except for chloride, accompanied by dramatic colour changes visible to the naked eye. These changes were determined to be due to the deprotonation of the central N-H proton and not due to hydrogen bonding based on (1)H/(15)N NMR titration studies with acetate in DMSO-d6-0.5% water. Direct evidence for deprotonation was confirmed by the disappearance of the central thiourea proton and the formation of acetic acid. DFT and charge distribution calculations suggest that for all four compounds the central N-H proton is the most acidic. Hence, the anion chemosensors operate by a deprotonation mechanism of the central N-H proton rather than by hydrogen bonding as is often reported.

  19. Authentication of beef versus horse meat using 60 MHz 1H NMR spectroscopy

    PubMed Central

    Jakes, W.; Gerdova, A.; Defernez, M.; Watson, A.D.; McCallum, C.; Limer, E.; Colquhoun, I.J.; Williamson, D.C.; Kemsley, E.K.

    2015-01-01

    This work reports a candidate screening protocol to distinguish beef from horse meat based upon comparison of triglyceride signatures obtained by 60 MHz 1H NMR spectroscopy. Using a simple chloroform-based extraction, we obtained classic low-field triglyceride spectra from typically a 10 min acquisition time. Peak integration was sufficient to differentiate samples of fresh beef (76 extractions) and horse (62 extractions) using Naïve Bayes classification. Principal component analysis gave a two-dimensional “authentic” beef region (p = 0.001) against which further spectra could be compared. This model was challenged using a subset of 23 freeze–thawed training samples. The outcomes indicated that storing samples by freezing does not adversely affect the analysis. Of a further collection of extractions from previously unseen samples, 90/91 beef spectra were classified as authentic, and 16/16 horse spectra as non-authentic. We conclude that 60 MHz 1H NMR represents a feasible high-throughput approach for screening raw meat. PMID:25577043

  20. Application of in operando UV/Vis spectroscopy in lithium-sulfur batteries.

    PubMed

    Patel, Manu U M; Dominko, Robert

    2014-08-01

    Application of UV/Vis spectroscopy for the qualitative and quantitative determination of differences in the mechanism of lithium-sulfur battery behavior is presented. With the help of catholytes prepared from chemically synthesized stoichiometric mixtures of lithium and sulfur, calibration curves for two different types of electrolyte can be constructed. First-order derivatives of UV/Vis spectra show five typical derivative peak positions in both electrolytes. In operando measurements show a smooth change in the UV/Vis spectra in the wavelength region between λ=650 and 400 nm. Derivatives are in agreement with derivative peak positions observed with catholytes. Recalculation of normalized reflections of UV/Vis spectra obtained in operando mode enable the formation of polysulfides and their concentrations to be followed. In such a way, it is possible to distinguish differences in the mechanism of polysulfide shuttling between two electrolytes and to correlate differences in capacity fading.

  1. Metabolomic by 1H NMR spectroscopy differentiates "Fiano di Avellino" white wines obtained with different yeast strains.

    PubMed

    Mazzei, Pierluigi; Spaccini, Riccardo; Francesca, Nicola; Moschetti, Giancarlo; Piccolo, Alessandro

    2013-11-13

    We employed (1)H NMR spectroscopy to examine the molecular profile of a white "Fiano di Avellino" wine obtained through fermentation by either a commercial or a selected autochthonous Saccharomyces cerevisiae yeast starter. The latter was isolated from the same grape variety used in the wine-making process in order to strengthen the relationship between wine molecular quality and its geographical origin. (1)H NMR spectra, where water and ethanol signals were suppressed by a presaturated T1-edited NMR pulse sequence, allowed for definition of the metabolic content of the two differently treated wines. Elaboration of NMR spectral data by multivariate statistical analyses showed that the two different yeasts led to significant diversity in the wine metabolomes. Our results indicate that metabolomics by (1)H NMR spectroscopy combined with multivariate statistical analysis enables wine differentiation as a function of yeast species and other wine-making factors, thereby contributing to objectively relate wine quality to the terroir.

  2. Qualitative and Quantitative Control of Carbonated Cola Beverages Using 1H NMR Spectroscopy

    PubMed Central

    2012-01-01

    1H Nuclear magnetic resonance (NMR) spectroscopy (400 MHz) was used in the context of food surveillance to develop a reliable analytical tool to differentiate brands of cola beverages and to quantify selected constituents of the soft drinks. The preparation of the samples required only degassing and addition of 0.1% of TSP in D2O for locking and referencing followed by adjustment of pH to 4.5. The NMR spectra obtained can be considered as “fingerprints” and were analyzed by principal component analysis (PCA). Clusters from colas of the same brand were observed, and significant differences between premium and discount brands were found. The quantification of caffeine, acesulfame-K, aspartame, cyclamate, benzoate, hydroxymethylfurfural (HMF), sulfite ammonia caramel (E 150D), and vanillin was simultaneously possible using external calibration curves and applying TSP as internal standard. Limits of detection for caffeine, aspartame, acesulfame-K, and benzoate were 1.7, 3.5, 0.8, and 1.0 mg/L, respectively. Hence, NMR spectroscopy combined with chemometrics is an efficient tool for simultaneous identification of soft drinks and quantification of selected constituents. PMID:22356160

  3. 1H-HRMAS NMR study of smoked Atlantic salmon (Salmo salar).

    PubMed

    Castejón, David; Villa, Palmira; Calvo, Marta M; Santa-María, Guillermo; Herraiz, Marta; Herrera, Antonio

    2010-09-01

    High-resolution magic angle spinning (HRMAS) NMR spectroscopic data of smoked Atlantic salmon (Salmo salar) were fully assigned by combination of one- and two-dimensional-HRMAS experiments. Complete representative spectra, obtained after few minutes of analysis time, revealed a large number of minor and major compounds in the sample. The methodology is limited by the low sensitivity of NMR, and therefore HRMAS only enables the determination of the most relevant components. These were fatty acids (FAs), carbohydrates, nucleoside derivatives, osmolytes, amino acids, dipeptides and organic acids. For the first time, spectra were resolved sufficiently to allow semiquantitative determination in intact muscle of the highly polyunsaturated FA 22:6 omega-3. Additionally, the feasibility of (1)H-HRMAS NMR metabolite profiling was tested to identify some bioactive compounds during storage. This profiling was carried out by the non-destructive and direct analysis (i.e. without requiring sample preparation and multiple step procedures) of intact salmon muscle. The proposed procedure can be applied to a large number of samples with high throughput due to the short time of analysis and quick evaluation of the data.

  4. Thermal degradation in a trimodal poly(dimethylsiloxane) network studied by (1)H multiple quantum NMR.

    PubMed

    Giuliani, Jason R; Gjersing, Erica L; Chinn, Sarah C; Jones, Ticora V; Wilson, Thomas S; Alviso, Cynthia T; Herberg, Julie L; Pearson, Mark A; Maxwell, Robert S

    2007-11-15

    Thermal degradation of a filled, cross-linked siloxane material synthesized from poly(dimethylsiloxane) chains of three different average molecular weights and with two different cross-linking species has been studied by (1)H multiple quantum (MQ) NMR methods. Multiple domains of polymer chains were detected by MQ NMR exhibiting residual dipolar coupling () values of 200 and 600 Hz, corresponding to chains with high average molecular weight between cross-links and chains with low average molecular weight between cross-links or near the multifunctional cross-linking sites. Characterization of the values and changes in distributions present in the material were studied as a function of time at 250 degrees C and indicate significant time-dependent degradation. For the domains with low , a broadening in the distribution was observed with aging time. For the domain with high , increases in both the mean and the width in were observed with increasing aging time. Isothermal thermal gravimetric analysis reveals a 3% decrease in weight over 20 h of aging at 250 degrees C. Degraded samples also were analyzed by traditional solid-state (1)H NMR techniques, and off-gassing products were identified by solid-phase microextraction followed by gas chromatography-mass spectrometry. The results, which will be discussed here, suggest that thermal degradation proceeds by complex competition between oxidative chain scissioning and postcuring cross-linking that both contribute to embrittlement.

  5. Thermal degradation in a trimodal PDMS network by 1H Multiple Quantum NMR

    SciTech Connect

    Giuliani, J R; Gjersing, E L; Chinn, S C; Jones, T V; Wilson, T S; Alviso, C T; Herberg, J L; Pearson, M A; Maxwell, R S

    2007-06-06

    Thermal degradation of a filled, crosslinked siloxane material synthesized from PDMS chains of three different average molecular weights and with two different crosslinking species has been studied by {sup 1}H Multiple Quantum (MQ) NMR methods. Multiple domains of polymer chains were detected by MQ NMR exhibiting Residual Dipolar Coupling (<{Omega}{sub d}>) values of 200 Hz and 600 Hz, corresponding to chains with high average molecular weight between crosslinks and chains with low average molecular weight between crosslinks or near the multifunctional crosslinking sites. Characterization of the <{Omega}{sub d}> values and changes in <{Omega}{sub d}> distributions present in the material were studied as a function of time at 250 C and indicates significant time dependent degradation. For the domains with low <{Omega}{sub d}>, a broadening in the distribution was observed with aging time. For the domain with high <{Omega}{sub d}>, increases in both the mean <{Omega}{sub d}> and the width in <{Omega}{sub d}> were observed with increasing aging time. Isothermal Thermal Gravimetric Analysis (TGA) reveals a 3% decrease in weight over 20 hours of aging at 250 C. Degraded samples also were analyzed by traditional solid state {sup 1}H NMR techniques and offgassing products were identified by Solid Phase MicroExtraction followed by Gas Chromatography-Mass Spectrometry (SPME GC-MS). The results, which will be discussed here, suggest that thermal degradation proceeds by complex competition between oxidative chain scissioning and post-curing crosslinking that both contribute to embrittlement.

  6. Determination of polydimethylsiloxanes by 1H-NMR in wine and edible oils.

    PubMed

    Mojsiewicz-Pieńkowska, K; Jamrógiewicz, Z; Łukasiak, J

    2003-05-01

    Fourier transform (1)H-nuclear magnetic resonance (NMR) spectroscopy was suitable for the quantitative determination of polydimethylsiloxanes (PDMS) in wine and edible oil samples. This approach offers highly specific qualitative and quantitative analysis due to silicone-specific location of proton signals linked to carbon atoms located directly next to silicon atoms (0-0.5 ppm), as well as a different location of signals in the range for different organosilicon structures. The method can be used for the control of PDMS at regulatory limits in foodstuffs (10 mg kg(-1)) using hexamethyldisiloxane (HDMS) as an internal standard. Samples were prepared by extraction under suitable conditions to separate the analyte, and with analyte enrichment before (1)H-NMR analysis. Analytical procedures were developed to permit the determination of PDMS at 0.06 mg kg(-1) in wine and at 6 mg kg(-1) in edible oils samples using readily available NMR instrumentation. It was, however, possible to lower the limit of detection to 6 microg kg(-1) for wine and to 60 microg kg(-1) for edible oils using a higher field instrument (500 MHz). Relative standard deviations (S(r)) were obtained for wine (0.028) and for oil samples (0.043), which when compared with values obtained for samples spiked with PDMS (0.021) indicated that the sample preparation was the main factor determining the precision of the method. The average recovery rates for PDMS were 97 and 95% for wine and edible oils, respectively. PDMS was detected in four brands of Italian wine, with Chianti-Rafaello containing the highest concentration (0.35 mg kg(-1)), and in four types of edible oils, highest concentration (11.9 mg kg(-1)) being found in Italian corn oil. None of the levels of PDMS found in the food samples exceeded the permissible standards laid down by the Codex Alimentarius Commission (10 mg kg(-1)), with the exception of the one corn oil sample.

  7. Monitoring the on-line titration of enantiomeric omeprazole employing continuous-flow capillary microcoil 1H NMR spectroscopy.

    PubMed

    Hentschel, Petra; Holtin, Karsten; Steinhauser, Lisa; Albert, Klaus

    2012-12-01

    The titration of the (S)-enantiomer of omeprazole with the (R)-enantiomer in chloroform-d(1) is monitored by continuous-flow capillary microcoil (1)H NMR spectroscopy employing a microcoil with a detection volume of 1.5 µl. The observed changes of the (1)H NMR chemical shifts indicate the formation of a heterochiral (R,S) dimer of omeprazole via its sulfinyl group and the NH group of the benzimidazole ring.

  8. Measurement of Heme Ruffling Changes in MhuD Using UV-vis Spectroscopy.

    PubMed

    Graves, Amanda B; Graves, Max T; Liptak, Matthew D

    2016-04-28

    For decades it has been known that an out-of-plane ruffling distortion of heme perturbs its UV-vis absorption (Abs) spectrum, but whether increased ruffling induces a red or blue shift of the Soret band has remained a topic of debate. This debate has been resolved by the spectroscopic and computational characterization of Mycobacterium tuberculosis MhuD presented here, an enzyme that converts heme, oxygen, and reducing equivalents to nonheme iron and mycobilin. W66F and W66A MhuD have been characterized using (1)H nuclear magnetic resonance, Abs, and magnetic circular dichroism spectroscopies, and the data have been used to develop an experimentally validated theoretical model of ruffled, ferric heme. The PBE density functional theory (DFT) model that has been developed accurately reproduces the observed spectral changes from wild type enzyme, and the underlying quantum mechanical origins of these ruffling-induced changes were revealed by analyzing the PBE DFT description of the electronic structure. Small amounts of heme ruffling have no influence on the energy of the Q-band and blue-shift the Soret band due to symmetry-allowed mixing of the Fe 3dxy and porphyrin a2u orbitals. Larger amounts of ruffling red-shift both the Q and Soret bands due to disruption of π-bonding within the porphyrin ring.

  9. (1)H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer.

    PubMed

    Petersen, Bent O; Nilsson, Mathias; Bøjstrup, Marie; Hindsgaul, Ole; Meier, Sebastian

    2014-05-01

    A plethora of biological and biotechnological processes involve the enzymatic remodelling of carbohydrates in complex mixtures whose compositions affect both the processes and products. In the current study, we employed high-resolution (1)H NMR spectroscopy for the analysis of cereal-derived carbohydrate mixtures as exemplified on six beer samples of different styles. Structural assignments of more than 50 carbohydrate moieties were obtained using (1)H1-(1)H2 groups as structural reporters. Spectroscopically resolved carbohydrates include more than ''20 different'' small carbohydrates with more than 38 isomeric forms in addition to cereal polysaccharide fragments with suspected organoleptic and prebiotic function. Structural motifs at the cleavage sites of starch, β-glucan and arabinoxylan fragments were identified, showing different extent and specificity of enzymatic polysaccharide cleavage during the production of different beer samples. Diffusion ordered spectroscopy supplied independent size information for the characterisation and identification of polysaccharide fragments, indicating the presence especially of high molecular weight arabinoxylan fragments in the final beer.

  10. Vicinal 1H-1H NMR coupling constants from density functional theory as reliable tools for stereochemical analysis of highly flexible multichiral center molecules.

    PubMed

    López-Vallejo, Fabian; Fragoso-Serrano, Mabel; Suárez-Ortiz, Gloria Alejandra; Hernández-Rojas, Adriana C; Cerda-García-Rojas, Carlos M; Pereda-Miranda, Rogelio

    2011-08-05

    A protocol for stereochemical analysis, based on the systematic comparison between theoretical and experimental vicinal (1)H-(1)H NMR coupling constants, was developed and applied to a series of flexible compounds (1-8) derived from the 6-heptenyl-5,6-dihydro-2H-pyran-2-one framework. The method included a broad conformational search, followed by geometry optimization at the DFT B3LYP/DGDZVP level, calculation of the vibrational frequencies, thermochemical parameters, magnetic shielding tensors, and the total NMR spin-spin coupling constants. Three scaling factors, depending on the carbon atom hybridizations, were found for the (1)H-C-C-(1)H vicinal coupling constants: f((sp3)-(sp3)) = 0.910, f((sp3)-(sp2)) = 0.929, and f((sp2)-(sp2))= 0.977. A remarkable correlation between the theoretical (J(pre)) and experimental (1)H-(1)H NMR (J(exp)) coupling constants for spicigerolide (1), a cytotoxic natural product, and some of its synthetic stereoisomers (2-4) demonstrated the predictive value of this approach for the stereochemical assignment of highly flexible compounds containing multiple chiral centers. The stereochemistry of two natural 6-heptenyl-5,6-dihydro-2H-pyran-2-ones (14 and 15) containing diverse functional groups in the heptenyl side chain was also analyzed by application of this combined theoretical and experimental approach, confirming its reliability. Additionally, a geometrical analysis for the conformations of 1-8 revealed that weak hydrogen bonds substantially guide the conformational behavior of the tetraacyloxy-6-heptenyl-2H-pyran-2-ones.

  11. Response to the Letter to the Editor regarding "Determination of the fatty acid profile by 1H-NMR spectroscopy."

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In expansion of previous work (G. Knothe, J.A. Kenar, Determination of the fatty acid profile by 1H-NMR spectroscopy, Eur. J. Lipid Sci. Technol. 2004, 106, 88-96), an additional approach is discussed for quantitating saturated fatty acids in the fatty acid profiles of common vegetable oils by 1H-NM...

  12. Discovering [superscript 13]C NMR, [superscript 1]H NMR, and IR Spectroscopy in the General Chemistry Laboratory through a Sequence of Guided-Inquiry Exercises

    ERIC Educational Resources Information Center

    Iler, H. Darrell; Justice, David; Brauer, Shari; Landis, Amanda

    2012-01-01

    This sequence of three guided-inquiry labs is designed for a second-semester general chemistry course and challenges students to discover basic theoretical principles associated with [superscript 13]C NMR, [superscript 1]H NMR, and IR spectroscopy. Students learn to identify and explain basic concepts of magnetic resonance and vibrational…

  13. Solution behavior and complete sup 1 H and sup 13 C NMR assignments of the coenzyme B sub 12 derivative (5 prime -deoxyadenosyl)cobinamide using modern 2D NMR experiments, including 600-MHz sup 1 H NMR data

    SciTech Connect

    Pagano, T.G.; Yohannes, P.G.; Marzilli, L.G. ); Hay, B.P.; Scott, J.R.; Finke, R.G. )

    1989-02-15

    Two-dimensional (2D) NMR methods have been used to assign completely the {sup 1}H and {sup 13}C NMR spectra of the (5{prime}-deoxyadenosyl)cobinamide cation (AdoCbi{sup +}) in D{sub 2}O. Most of the {sup 1}H spectral assignments were made by using 2D homonuclear shift correlation spectroscopy (COSY), homonuclear Hartmann-Hahn spectroscopy (HOHAHA), absorption-mode (phase sensitive) 2D nuclear Overhauser effect (NOE) spectroscopy, and spin-locked NOE spectroscopy (also called ROESY, for rotating-frame Overhauser enhancement spectroscopy). Most of the protonated carbon resonances were assigned by using {sup 1}H-detected heteronuclear multiple-quantum coherence (HMQC) spectroscopy. The nonprotonated carbon resonances, as well as the remaining unassigned {sup 1}H and {sup 13}C NMR signals, were assigned from long-range {sup 1}H-{sup 13}C connectivities determined from {sup 1}H-detected multiple-bond heteronuclear multiple-quantum coherence spectroscopy (HMBC). Comparison of the {sup 13}C chemical shifts and {sup 1}H NOEs of AdoCbi{sup +} with those of coenzyme B{sup 12} ((5{prime}-deoxyadenosyl)cobalamin) and its benzimidazole-protonated, base-off form indicates that the electronic properties and structure of AdoCbi{sup +} are similar to that of coenzyme B{sup 12} in the protonated, base-off form. The {sup 13}C chemical shifts of most of the carbons of AdoCbi{sup +} do not vary significantly from those of base-off, benzimidazole-protonated coenzyme B{sup 12}, indicating that the electronic environment of the corrin ring is also similar in both compounds. However, significant differences in the chemical shifts of some of the corresponding carbons of the b, d, e, and f corrin side chains in AdoCbi{sup +} and in base-off, benzimidazole-protonated coenzyme B{sub 12} indicate that the positions of these side chains may be different in AdoCbi{sup +} compared to base-off coenzyme B{sup 12}.

  14. DFT calculations of 1H and 13C NMR chemical shifts in transition metal hydrides.

    PubMed

    del Rosal, I; Maron, L; Poteau, R; Jolibois, F

    2008-08-14

    Transition metal hydrides are of great interest in chemistry because of their reactivity and their potential use as catalysts for hydrogenation. Among other available techniques, structural properties in transition metal (TM) complexes are often probed by NMR spectroscopy. In this paper we will show that it is possible to establish a viable methodological strategy in the context of density functional theory, that allows the determination of 1H NMR chemical shifts of hydride ligands attached to transition metal atoms in mononuclear systems and clusters with good accuracy with respect to experiment. 13C chemical shifts have also been considered in some cases. We have studied mononuclear ruthenium complexes such as Ru(L)(H)(dppm)2 with L = H or Cl, cationic complex [Ru(H)(H2O)(dppm)2]+ and Ru(H)2(dppm)(PPh3)2, in which hydride ligands are characterized by a negative 1H NMR chemical shift. For these complexes all calculations are in relatively good agreement compared to experimental data with errors not exceeding 20% except for the hydrogen atom in Ru(H)2(dppm)(PPh3)2. For this last complex, the relative error increases to 30%, probably owing to the necessity to take into account dynamical effects of phenyl groups. Carbonyl ligands are often encountered in coordination chemistry. Specific issues arise when calculating 1H or 13C NMR chemical shifts in TM carbonyl complexes. Indeed, while errors of 10 to 20% with respect to experiment are often considered good in the framework of density functional theory, this difference in the case of mononuclear carbonyl complexes culminates to 80%: results obtained with all-electron calculations are overall in very satisfactory agreement with experiment, the error in this case does not exceed 11% contrary to effective core potentials (ECPs) calculations which yield errors always larger than 20%. We conclude that for carbonyl groups the use of ECPs is not recommended, although their use could save time for very large systems, for

  15. Composition of beer by 1H NMR spectroscopy: effects of brewing site and date of production.

    PubMed

    Almeida, Cláudia; Duarte, Iola F; Barros, António; Rodrigues, João; Spraul, Manfred; Gil, Ana M

    2006-02-08

    A principal component analysis (PCA) of 1H NMR spectra of beers differing in production site (A, B, C) and date is described, to obtain information about composition variability. First, lactic and pyruvic acids contents were found to vary significantly between production sites, good reproducibility between dates being found for site A but not for sites B and C beers. Second, site B beers were clearly distinguished by the predominance of linear dextrins, while A and C beers were richer in branched dextrins. Carbohydrate reproducibility between dates is poorer for site C with dextrin branching degree varying significantly. Finally, all production sites were successfully distinguished by their contents in adenosine/inosine, uridine, tyrosine/tyrosol, and 2-phenylethanol, reproducibility between dates being again poorer for site C. Interpretation of the above compositional differences is discussed in terms of the biochemistry taking place during brewing, and possible applications of the method in brewing process control are envisaged.

  16. 1H NMR study of the complexation of aromatic drugs with dimethylxanthine derivatives

    NASA Astrophysics Data System (ADS)

    Hernandez Santiago, A. A.; Gonzalez Flores, M.; Rosas Castilla, S. A.; Cervantes Tavera, A. M.; Gutierrez Perez, R.; Khomich, V. V.; Ovchinnikov, D. V.; Parkes, H. G.; Evstigneev, M. P.

    2012-02-01

    With an aim of searching efficient interceptors of aromatic drugs, the self- and hetero-association of dimethylxanthine derivatives with different structures, selected according to Strategy 1 (variation of the position of methyl groups) and Strategy 2 (variation of the length of sbnd (CH2)nsbnd COOH group), with aromatic drug molecules: Ethidium Bromide, Proflavine and Daunomycin, were studied using 1H NMR spectroscopy. It was found that the association proceeds in a form of stacking-type complexation and its energetics is relatively independent on the structure of the dimethylxanthines. However, on average, the dimethylxanthines possess higher hetero-association constant and, hence, higher interceptor ability as compared to the trimethylxanthine, Caffeine, used during the past two decades as a typical interceptor molecule.

  17. Determination of rate constants of N-alkylation of primary amines by 1H NMR spectroscopy.

    PubMed

    Li, Chenghong

    2013-09-05

    Macromolecules containing N-diazeniumdiolates of secondary amines are proposed scaffolds for controlled nitrogen oxide (NO) release medical applications. Preparation of these compounds often involves converting primary amine groups to secondary amine groups through N-alkylation. However, N-alkylation results in not only secondary amines but tertiary amines as well. Only N-diazeniumdiolates of secondary amines are suitable for controlled NO release; therefore, the yield of secondary amines is crucial to the total NO load of the carrier. In this paper, (1)H NMR spectroscopy was used to estimate the rate constants for formation of secondary amine (k1) and tertiary amine (k2) for alkylation reagents such as propylene oxide (PO), methyl acrylate (MA), and acrylonitrile (ACN). At room temperature, the ratio of k2/k1 for the three reactions was found to be around 0.50, 0.026, and 0.0072.

  18. Quantitative 1H NMR: Development and Potential of an Analytical Method – an Update

    PubMed Central

    Pauli, Guido F.; Gödecke, Tanja; Jaki, Birgit U.; Lankin, David C.

    2012-01-01

    Covering the literature from mid-2004 until the end of 2011, this review continues a previous literature overview on quantitative 1H NMR (qHNMR) methodology and its applications in the analysis of natural products (NPs). Among the foremost advantages of qHNMR is its accurate function with external calibration, the lack of any requirement for identical reference materials, a high precision and accuracy when properly validated, and an ability to quantitate multiple analytes simultaneously. As a result of the inclusion of over 170 new references, this updated review summarizes a wealth of detailed experiential evidence and newly developed methodology that supports qHNMR as a valuable and unbiased analytical tool for natural product and other areas of research. PMID:22482996

  19. Cloud point, fluorimetric and 1H NMR studies of ibuprofen-polymer systems

    NASA Astrophysics Data System (ADS)

    Khan, Iqrar Ahmad; Anjum, Kahkashan; Koya, P. Ajmal; Qadeer, Atiytul; Kabir-ud-Din

    2014-01-01

    Influence of six polymers viz. hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC), polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP), sodium carboxy methyl cellulose (NaCMC) and dextran sulfate (DxS) on solution properties of amphiphilic drug ibuprofen (IBF) has been described in this work. As only HPMC showed the clouding behavior (among the polymers employed herein), its cloud point (CP) was studied in detail in presence of varying amounts of IBF containing different fixed concentrations of inorganic salts (NaCl, NaNO3, Na2SO4, KBr and KNO3). Presence of all these salts had CP reducing effect. By means of steady state fluorescence quenching studies, average aggregation number of IBF aggregates (Nagg) in the presence of varying amounts of the mentioned polymers were evaluated and discussed. 1H NMR studies show that the magnitude of chemical shifts (δ) varies with the nature of the polymer.

  20. (1) H-NMR with Multivariate Analysis for Automobile Lubricant Comparison.

    PubMed

    Kim, Siwon; Yoon, Dahye; Lee, Dong-Kye; Yoon, Changshin; Kim, Suhkmann

    2017-02-23

    Identification of suspected automobile-related lubricants could provide valuable information in forensic cases. We examined that automobile lubricants might exhibit the chemometric characteristics to their individual usages. To compare the degree of clustering in the plots, we co-plotted general industrial oils that were highly dissimilar with automobile lubricants in additive compositions. (1) H-NMR spectroscopy was used with multivariate statistics as a tool for grouping, clustering, and identification of automobile lubricants in laboratory conditions. We analyzed automobile lubricants including automobile engine oils, automobile transmission oils, automobile gear oils, and motorcycle oils. In contrast to the general industrial oils, automobile lubricants showed relatively high tendencies of clustering to their usages. Our pilot study demonstrated that the comparison of known and questioned samples to their usages might be possible in forensic fields.

  1. A subzero 1H NMR relaxation investigation of water dynamics in tomato pericarp.

    PubMed

    Foucat, Loïc; Lahaye, Marc

    2014-09-01

    (1)H NMR relaxation times (T1 and T2) were measured at low field (0.47 T) in pericarp tissues of three tomato genotypes (Ferum, LA0147 and Levovil) at subzero temperature (-20 °C) and two ripening stages (mature green and red). The unfrozen water dynamics was characterised by two T1 and three T2 components. The relaxation time values and their associated relative populations allowed differentiating the ripening stage of only LA0147 and Levovil lines. But the three genotypes were unequivocally discriminated at the red ripe stage. The unfrozen water distribution was discussed in terms of specific interactions, especially with sugars, in relation with their osmoprotectant effects.

  2. Essential Parameters for Structural Analysis and Dereplication by 1H NMR Spectroscopy

    PubMed Central

    2015-01-01

    The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain 1H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1–1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen (1H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms. PMID:24895010

  3. Age-Related 1H NMR Characterization of Cerebrospinal Fluid in Newborn and Young Healthy Piglets

    PubMed Central

    Barone, Francesca; Elmi, Alberto; Romagnoli, Noemi; Bacci, Maria Laura

    2016-01-01

    When it comes to neuroscience, pigs represent an important animal model due to their resemblance with humans’ brains for several patterns including anatomy and developmental stages. Cerebrospinal fluid (CSF) is a relatively easy-to-collect specimen that can provide important information about neurological health and function, proving its importance as both a diagnostic and biomedical monitoring tool. Consequently, it would be of high scientific interest and value to obtain more standard physiological information regarding its composition and dynamics for both swine pathology and the refinement of experimental protocols. Recently, proton nuclear magnetic resonance (1H NMR) spectroscopy has been applied in order to analyze the metabolomic profile of this biological fluid, and results showed the technique to be highly reproducible and reliable. The aim of the present study was to investigate in both qualitative and quantitative manner the composition of Cerebrospinal Fluid harvested form healthy newborn (5 days old-P5) and young (30-P30 and 50-P50 days old) piglets using 1H NMR Spectroscopy, and to analyze any possible difference in metabolites concentration between age groups, related to age and Blood-Brain-Barrier maturation. On each of the analyzed samples, 30 molecules could be observed above their limit of quantification, accounting for 95–98% of the total area of the spectra. The concentrations of adenine, tyrosine, leucine, valine, 3-hydroxyvalerate, 3-methyl-2-oxovalerate were found to decrease between P05 and P50, while the concentrations of glutamine, creatinine, methanol, trimethylamine and myo-inositol were found to increase. The P05-P30 comparison was also significant for glutamine, creatinine, adenine, tyrosine, leucine, valine, 3-hydroxyisovalerate, 3-methyl-2-oxovalerate, while for the P30-P50 comparison we found significant differences for glutamine, myo-inositol, leucine and trimethylamine. None of these molecules showed at P30 concentrations

  4. (1)H NMR-based metabolomic approach for understanding the fermentation behaviors of wine yeast strains.

    PubMed

    Son, Hong-Seok; Hwang, Geum-Sook; Kim, Ki Myong; Kim, Eun-Young; van den Berg, Frans; Park, Won-Mok; Lee, Cherl-Ho; Hong, Young-Shick

    2009-02-01

    (1)H NMR spectroscopy coupled with multivariate statistical analysis was used for the first time to investigate metabolic changes in musts during alcoholic fermentation and wines during aging. Three Saccharomyces cerevisiae yeast strains (RC-212, KIV-1116, and KUBY-501) were also evaluated for their impacts on the metabolic changes in must and wine. Pattern recognition (PR) methods, including PCA, PLS-DA, and OPLS-DA scores plots, showed clear differences for metabolites among musts or wines for each fermentation stage up to 6 months. Metabolites responsible for the differentiation were identified as valine, 2,3-butanediol (2,3-BD), pyruvate, succinate, proline, citrate, glycerol, malate, tartarate, glucose, N-methylnicotinic acid (NMNA), and polyphenol compounds. PCA scores plots showed continuous movements away from days 1 to 8 in all musts for all yeast strains, indicating continuous and active fermentation. During alcoholic fermentation, the highest levels of 2,3-BD, succinate, and glycerol were found in musts with the KIV-1116 strain, which showed the fastest fermentation or highest fermentative activity of the three strains, whereas the KUBY-501 strain showed the slowest fermentative activity. This study highlights the applicability of NMR-based metabolomics for monitoring wine fermentation and evaluating the fermentative characteristics of yeast strains.

  5. 1H NMR relaxation of water: a probe for surfactant adsorption on kaolin.

    PubMed

    Totland, Christian; Lewis, Rhiannon T; Nerdal, Willy

    2011-11-01

    In this study, (1)H NMR is used to investigate properties of sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB), and dodecyl trimethyl ammonium bromide (DTAB) adsorbed on kaolin by NMR T(1) and T(2) measurements of the water proton resonance. The results show that adsorbed surfactants form a barrier between sample water and the paramagnetic species present on the clay surface, thus significantly increasing the proton T(1) values of water. This effect is attributed to the amount of adsorbed surfactants and the arrangement of the surfactant aggregates. The total surface area covered by the cationic (DTAB and TTAB) and anionic (SDS) surfactants could be estimated from the water T(1) data and found to correspond to the fractions of negatively and positively charged surface area, respectively. For selected samples, the amount of paramagnetic species on the clay surface was reduced by treatment with hydrofluoric (HF) acid. For these samples, T(1) and T(2) measurements were taken in the temperature range 278-338 K, revealing detailed information on molecular mobility and nuclear exchange for the sample water that is related to surfactant behavior both on the surface and in the aqueous phase.

  6. 1H NMR-based metabolic profiling for evaluating poppy seed rancidity and brewing.

    PubMed

    Jawień, Ewa; Ząbek, Adam; Deja, Stanisław; Łukaszewicz, Marcin; Młynarz, Piotr

    2015-12-01

    Poppy seeds are widely used in household and commercial confectionery. The aim of this study was to demonstrate the application of metabolic profiling for industrial monitoring of the molecular changes which occur during minced poppy seed rancidity and brewing processes performed on raw seeds. Both forms of poppy seeds were obtained from a confectionery company. Proton nuclear magnetic resonance (1H NMR) was applied as the analytical method of choice together with multivariate statistical data analysis. Metabolic fingerprinting was applied as a bioprocess control tool to monitor rancidity with the trajectory of change and brewing progressions. Low molecular weight compounds were found to be statistically significant biomarkers of these bioprocesses. Changes in concentrations of chemical compounds were explained relative to the biochemical processes and external conditions. The obtained results provide valuable and comprehensive information to gain a better understanding of the biology of rancidity and brewing processes, while demonstrating the potential for applying NMR spectroscopy combined with multivariate data analysis tools for quality control in food industries involved in the processing of oilseeds. This precious and versatile information gives a better understanding of the biology of these processes.

  7. Combined Analysis of Stable Isotope, (1)H NMR, and Fatty Acid To Verify Sesame Oil Authenticity.

    PubMed

    Kim, Jeongeun; Jin, Gyungsu; Lee, Yunhee; Chun, Hyang Sook; Ahn, Sangdoo; Kim, Byung Hee

    2015-10-14

    The aim of this study was to verify the authenticity of sesame oils using combined analysis of stable isotope ratio, (1)H NMR spectroscopy, and fatty acid profiles of the oils. Analytical data were obtained from 35 samples of authentic sesame oils and 29 samples of adulterated sesame oils currently distributed in Korea. The orthogonal projection to latent structure discriminant analysis technique was used to select variables that most effectively verify the sesame oil authenticity. The variables include δ(13)C value, integration values of NMR peaks that signify the CH3 of n-3 fatty acids, CH2 between two C═C, protons from sesamin/sesamolin, and 18:1n-9, 18:3n-3, 18:2t, and 18:3t content values. The authenticity of 65 of 70 blind samples was correctly verified by applying the range of the eight variables found in the authentic sesame oil samples, suggesting that triple analysis is a useful approach to verify sesame oil authenticity.

  8. 1H HR-MAS NMR of carotenoids in aqueous samples and raw vegetables.

    PubMed

    Miglietta, M L; Lamanna, R

    2006-07-01

    Carotenoids are linear C40 tetraterpenoid hydrocarbons and represent a wide category of natural pigments. They are components of the pigment system of chloroplasts and are involved in the primary light absorption and the photon canalization of photosynthesis. Moreover, they also behave as quenchers of singlet oxygen, protecting cells and organisms against lipid peroxidation. Carotenoids have a strong lipophilic character and are usually analyzed in organic solvents. However, because of their biological activity, the characterization of these compounds in an aqueous environment or in the natural matrix is very important. One of the most important dietary carotenoids is beta-carotene, which has been extensively studied both in vivo and in model systems, but because of the low concentration and strong interaction with the biological matrix, beta-carotene has never been observed by NMR in solid aqueous samples.In the present work, a model system has been developed for the detection and identification of beta-carotene in solid aqueous samples by 1H HR-MAS NMR. The efficiency of the model has led to the identification of beta-carotene in a raw vegetable matrix.

  9. Complete 1H and 13C NMR assignments of six saponins from Sapindus trifoliatus.

    PubMed

    Grover, Rajesh K; Roy, Abhijeet D; Roy, Raja; Joshi, S K; Srivastava, Vandita; Arora, Sudershan K

    2005-12-01

    Complete 1H and 13C spectral assignments are reported for six saponins from the pericarp of Sapindus trifoliatus (Hindi name: Reetha) collected from Madhya Pradesh and Maharashtra, India, using only 1D and 2D NMR methods. The structures of the compounds were elucidated as hederagenin 3-O-(3-O-acetyl-beta-D-xylopyranosyl)-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha-L-ara-binopyranoside, hederagenin 3-O-(4-O-acetyl-beta-D-xylop-yranosyl)-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha-L-arabinop-yranoside, hederagenin 3-O-(3,4-O-diacetyl-beta-D-xylopy-ranosyl)-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha-L-arabinopy-ranoside, hederagenin 3-O-(3,4-O-diacetyl-alpha-L-arabinop-yranosyl)-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha-L-arabinop-yranoside, hederagenin 3-O-(beta-D-xylopyranosyl)-(1-3)-alpha-L-rhamnopyranosyl-(1-2)-alpha-L-arabinopyranoside and he-deragenin 3-O-(alpha-L-arabinopyranosyl)-(1-3)-alpha-L-rhamno-pyranosyl-(1-2)-alpha-L-arabinopyranoside. It is concluded that saponins of this complexity approach the limit of structural complexity, which can be solved by NMR alone, precisely and quickly.

  10. Secondary structure determination of human. beta. -endorphin by /sup 1/H NMR spectroscopy

    SciTech Connect

    Lichtarge, O.; Jardetzky, O.; Li, C.H.

    1987-09-08

    The /sup 1/H NMR spectra of human ..beta..-endorphin indicate that the peptide exists in random-coil form in aqueous solution but becomes helical in mixed solvent. Thermal denaturation NMR experiments show that in water there is no transition between 24 and 75/sup 0/C, while a slow noncooperative thermal unfolding is observed in a 60% methanol-40% water mixed solvent in the same temperature range. These findings are consistent with circular dichroism studies by other workers concluding that ..beta..-endorphin is a random coil in water but that it forms 50% ..cap alpha..-helix or more in mixed solvents. The peptide in the mixed water-methanol solvent was further studied by correlated spectroscopy (COSY) and nuclear Overhauser effect spectroscopy (NOESY) experiments. These allow a complete set of assignments to be made and establish two distinct stretches over which the solvent induces formation of ..cap alpha..-helices: the first occurs between Tyr-1 and Thr-12 and the second between Leu-14 and extending to Lys-28. There is evidence that the latter is capped by a turn occurring between Lys-28 and Glu-31. These helices form at the enkephalin receptor binding site, which is at the amino terminus, and at the morphine receptor binding site, located at the carboxyl terminus. The findings suggest that these two receptors may specifically recognize ..cap alpha..-helices.

  11. Arrangement and mobility of water in vermiculite hydrates followed by 1H NMR spectroscopy.

    PubMed

    Sanz, J; Herrero, C P; Serratosa, J M

    2006-04-20

    The arrangement of water molecules in one- and two-layer hydrates of high-charged vermiculites, saturated with alkaline (Li(+), Na(+)) and alkali-earth (Mg(2+), Ca(2+), Ba(2+)) cations, has been analyzed with (1)H NMR spectroscopy. Two different orientations for water molecules have been found, depending on the hydration state and the sites occupied by interlayer cations. As the amount of water increases, hydrogen bond interactions between water molecules increase at expenses of water-silicate interactions. This interaction favors water mobility in vermiculites. A comparison of the temperature dependence of relaxation times T(1) and T(2) for one and two-layer hydrates of Na-vermiculite shows that the rotations of water molecules around C(2)-axes and that of cation hydration shells around the c-axis is favored in the two-layer hydrate. In both hydrates, the anisotropic diffusion of water takes place at room temperature, preserving the orientation of water molecules relative to the silicate layers. Information obtained by NMR spectroscopy is compatible with that deduced by infrared spectroscopy and with structural studies carried out with X-ray and neutron diffraction techniques on single-crystals of vermiculite.

  12. 1H NMR characterization of a hen ovalbumin tyrosinamide N-linked oligosaccharide library.

    PubMed

    Corradi Da Silva, M L; Stubbs, H J; Tamura, T; Rice, K G

    1995-04-20

    A library of 15 N-linked oligosaccharide structures was prepared from ovalbumin and characterized using high-field NMR and mass spectrometry. The oligosaccharides were enzymatically released from ovalbumin glycopeptides, and the reducing ends were reacted with ammonium bicarbonate to form oligosaccharide-glycosylamines. These reacted with Boc-tyrosine-N-hydroxysuccinimide ester, resulting in a mixture of tyrosinamide-oligosaccharides. The Boc group was removed to expose an amine terminus which enhanced the resolution of tyrosinamide-oligosaccharides when chromatographed on reverse-phase HPLC. Ten major and five minor oligosaccharides were purified on a micromole scale and characterized using 1H NMR and FAB-MS. The structures include high-mannose, hybrid, and complex oligosaccharides possessing from two to five antenna, providing the most complete definition of ovalbumin N-linked oligosaccharides to date. The resulting library is well suited to biological studies due to the presence of a single terminal tyrosine residue on each oligosaccharide that allows radioiodination or the attachment of additional probes to these glycoconjugates prior to biological studies.

  13. Rapid determination of coenzyme Q10 in food supplements using 1H NMR spectroscopy.

    PubMed

    Monakhova, Yulia B; Ruge, Ingrid; Kuballa, Thomas; Lerch, Christiane; Lachenmeier, Dirk W

    2013-01-01

    A methodology utilizing 1H NMR spectroscopy has been developed to measure the concentration of coenzyme Q10 (CoQ10) in dietary supplements. For sample preparation, a very simple dilution with deuterated chloroform and addition of internal standard is sufficient. CoQ10 produces a distinct peak of the CH groups in the isoprene side chain of the molecule in the δ 5.15 - 5.05 ppm range, where it can be distinguished from other matrix compounds. The method was shown to be of adequate sensitivity with a limit of detection (LOD) of 7.8 mg/L, to control the CoQ10 content in the majority of the products. The precision expressed as relative standard deviation was around 5 %; linearity was observed from 14 to 2000 mg/L (R = 0.99). The developed methodology was applied for the analysis of 21 food supplements (capsules, tablets, and liquid products). On the basis of the labeled amounts, only two products contained substantially lower concentrations of CoQ10 (57 % and 51 %). All other concentrations varied between 83 % and 190 % with respect to labeling. The developed NMR method may be used by quality assurance laboratories for routine control of CoQ10 products.

  14. Organic solute changes with acidification in Lake Skjervatjern as shown by 1H-NMR spectroscopy

    USGS Publications Warehouse

    Malcolm, R.L.; Hayes, T.

    1994-01-01

    1H-NMR spectroscopy has been found to be a useful tool to establish possible real differences and trends between all natural organic solute fractions (fulvic acids, humic acids, and XAD-4 acids) after acid-rain additions to the Lake Skjervatjern watershed. The proton NMR technique used in this study determined the spectral distribution of nonexchangeable protons among four peaks (aliphatic protons; aliphatic protons on carbon ?? or attached to electronegative groups; protons on carbons attached to O or N heteroatoms; and aromatic protons). Differences of 10% or more in the respective peak areas were considered to represent a real difference. After one year of acidification, fulvic acids decreased 13% (relative) in Peak 3 protons on carbon attached to N and O heteratoms and exhibited a decrease in aromatic protons between 27% and 31%. Humic acids also exhibited an 11% relative decrease in aromatic protons as a result of acidification. After one year of acidification, real changes were shown in three of the four proton assignments in XAD-4 acids. Peak 1 aliphatic protons increased by 14% (relative), Peak 3 protons on carbons attached to O and N heteroatoms decreased by 13% (relative), and aromatic protons (Peak 4) decreased by 35% (relative). Upon acidification, there was a trend in all solutes for aromatic protons to decrease and aliphatic protons to increase. The natural variation in organic solutes as shown in the Control Side B of the lake from 1990 to 1991 is perhaps a small limitation to the same data interpretations of acid rain changes at the Lake Skjervatjern site, but the proton NMR technique shows great promise as an independent scientific tool to detect and support other chemical techniques in establishing organic solute changes with different treatments (i.e., additions of acid rain).

  15. Spatially localized sup 1 H NMR spectra of metabolites in the human brain

    SciTech Connect

    Hanstock, C.C. ); Rothman, D.L.; Jue, T.; Shulman, R.G. ); Prichard, J.W. )

    1988-03-01

    Using a surface coil, the authors have obtained {sup 1}H NMR spectra from metabolites in the human brain. Localization was achieved by combining depth pulses with image-selected in vivo spectroscopy magnetic field gradient methods. {sup 1}H spectra in which total creatine (3.03 ppm) has a signal/noise ratio of 95:1 were obtained in 4 min from 14 ml of brain. A resonance at 2.02 ppm consisting predominantly of N-acetylaspartate was measured relative to the creatine peak in gray and white matter, and the ratio was lower in the white matter. The spin-spin relaxation times of N-acetylaspartate and creatine were measured in white and gray matter and while creatine relaxation times were the same in both, the N-acetylaspartate relaxation time was longer in white matter. Lactate was detected in the normoxic brain and the average of three measurements was {approx}0.5 mM from comparison with the creatine plus phosphocreatine peak, which was assumed to be 10.5 mM.

  16. Towards high resolution ^1H NMR spectra of tannin colloidal aggregates

    NASA Astrophysics Data System (ADS)

    Mirabel, M.; Glories, Y.; Pianet, I.; Dufourc, E. J.

    1999-10-01

    The time dependent colloidal formation of tannins in hydro-alcoholic medium has been studied by 1H-NMR. Line broadening observed with time can be cancelled by making use of magic angle sample spinning (MASS) thus yielding sharp lines that allow structural studies. We used as an example catechin, a constitutive monomer of Bordeaux young red wine tannins. Chemical shift variations of polyphenol protons allow monitoring the time course of aggregation. La formation de tanins colloïdaux au cours du temps, en milieu hydroalcoolique, a été suivie par RMN-^1H. Un élargissement marqué des résonances est observé et peut être supprimé par la rotation de l'échantillon à l'angle magique ce qui ouvre tout un champ d'études structurales sur ces composés colloïdaux. L'exemple proposé est celui de la catéchine, monomère constitutif de tannins présents en grande quantité dans les vins rouges jeunes de Bordeaux. Des variations du déplacement chimique de certains protons polyphénoliques permettent de suivre l'évolution temporelle de l'agrégation.

  17. 1H Photo-CIDNP Enhancements in Heteronuclear Correlation NMR Spectroscopy

    PubMed Central

    Sekhar, Ashok; Cavagnero, Silvia

    2009-01-01

    Photochemically induced dynamic nuclear polarization (photo-CIDNP) is usually employed as a probe of solvent exposure, in biomolecular NMR. The potential of the photo-CIDNP effect for sensitivity enhancement, however, remains poorly explored. Here, we introduce 1H-photo-CIDNP in heteronuclear correlation spectroscopy at low laser irradiation power (1 W), and compare the sensitivity of various 1H-Photo-CIDNP-enhanced- (HPE) 1H◻15N heteronuclear correlation pulse sequences, including HSQC, HMQC, and SOFAST-HMQC, in terms of their ability to detect the Trp indole Hε1 resonance. Both Trp and the Trp-containing protein apoHmpH were analyzed using flavin mononucleotide as photosensitizer in aqueous solutions either containing or lacking urea. We find that 1H◻15N photo-CIDNP-SOFAST-HMQC, denoted here as HPE-SOFAST-HMQC, yields a two-fold higher signal-to-noise per unit time than the parent SOFAST-HMQC for the solvent-exposed Trp of urea-unfolded apoHmpH. Thus, HPE-SOFAST-HMQC is the most sensitive heteronuclear correlation pulse sequence for the detection of solvent-exposed Trp. PMID:19462951

  18. 1H-NMR characterization of poly(ethylene glycol) and polydimethylsiloxane copolymer

    NASA Astrophysics Data System (ADS)

    Zainuddin, Ain Athirah; Othaman, Rizafizah; Noor, Wan Syaidatul Aqma Wan Mohd; Anuar, Farah Hannan

    2016-11-01

    This paper describes the synthesis and characterization of poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) copolymers. The copolymers were synthesized by reacting hydroxyl group (-OH) of poly(ethylene glycol) (PEG) and polydimetylsiloxane (PDMS) with isocyanate group (R-N=C=O) of 1,6-hexamethylene diisocyanate (HMDI). The reaction was carried out at room temperature. The copolymers were synthesized in three different compositions which differ in molar ratios of PEG to PDMS. The ratios (PEG:PDMS) used were 2:6. 3:5 and 4:4. The formation of the copolymers was characterized by 1H Nuclear Magnetic Resonance (1H-NMR) for structural determination. The presence of proton signal at 4.80 ppm which belongs to the proton of urethane group indicates the formation of urethane links. The formation of urethane links showed that two homopolymers were linked together by HMDI to form longer copolymer chains. It is worth to note that the sequence of PEG and PDMS along the copolymer chain is random.

  19. UV-Vis reflection spectroscopy under variable angle incidence at the air-liquid interface.

    PubMed

    Roldán-Carmona, Cristina; Rubia-Payá, Carlos; Pérez-Morales, Marta; Martín-Romero, María T; Giner-Casares, Juan J; Camacho, Luis

    2014-03-07

    The UV-Vis reflection spectroscopy (UV-Vis-RS) in situ at the air-liquid interface provides information about tilt and aggregation of chromophores in Langmuir monolayers. This information is particularly important given in most cases the chromophore is located at the polar region of the Langmuir monolayer. This region of the Langmuir monolayers has been hardly accessible by other experimental techniques. In spite of its enormous potential, the application of UV-Vis-RS has been limited mainly to reflection measurements under light normal incidence or at lower incidence angles than the Brewster angle. Remarkably, this technique is quite sensitive to the tilt of the chromophores at values of incidence angles close to or larger than the Brewster angle. Therefore, a novel method to obtain the order parameter of the chromophores at the air-liquid interface by using s- and p-polarized radiation at different incidence angles is proposed. This method allowed for the first time the experimental observation of the two components with different polarization properties of a single UV-Vis band at the air-liquid interface. The method of UV-Vis spectroscopy under variable angle incidence is presented as a new tool for obtaining rich detailed information on Langmuir monolayers.

  20. 1H NMR to investigate metabolism and energy supply in rhesus macaque sperm.

    PubMed

    Lin, Ching-Yu; Hung, Pei-hsuan; VandeVoort, Catherine A; Miller, Marion G

    2009-07-01

    Sperm ATP is derived primarily from either glycolysis or mitochondrial oxidative phosphorylation. In the present studies, (1)H NMR spectroscopy was used to characterize the metabolite profile in primate sperm treated either with alpha-chlorohydrin (ACH), a known inhibitor of sperm glycolysis or pentachlorophenol (PCP), an uncoupler of oxidative phosphorylation. Sperm were collected from monkeys in the fall and spring, washed and incubated with either the media control, ACH (0.5mM) or PCP (50 microM). Using principal components analysis, PC1 scores plot indicated that the greatest level of variance was found between fall and spring samples and not chemical-treated samples. However, PC4 scores plot did show a consistent effect of ACH treatment. From the PC1 loadings plot, metabolites contributing to the seasonal differences were higher levels of formate in the fall and higher levels of carnitine and acetylcarnitine in the spring as well as possible differences in lipoprotein content. The PC4 loadings plot indicated that ACH treatment decreased lactate and ATP consistent with inhibition of glycolysis. Carnitine also was decreased and acetylcarnitine increased although the latter was not statistically significant. With PCP-treated sperm, no difference between control and treated samples could be discerned suggesting either that primate sperm are insensitive to uncoupling agents or that glycolysis played the more important role in maintaining sperm ATP levels. Overall, NMR studies may prove useful in the development of metabolomic markers that signal sperm metabolic impairments and have the potential to provide useful biomarkers for reproductive health.

  1. 1H-NMR analysis provides a metabolomic profile of patients with multiple sclerosis

    PubMed Central

    Cocco, Eleonora; Murgia, Federica; Lorefice, Lorena; Barberini, Luigi; Poddighe, Simone; Frau, Jessica; Fenu, Giuseppe; Coghe, Giancarlo; Murru, Maria Rita; Murru, Raffaele; Del Carratore, Francesco; Atzori, Luigi

    2015-01-01

    Objective: To investigate the metabolomic profiles of patients with multiple sclerosis (MS) and to define the metabolic pathways potentially related to MS pathogenesis. Methods: Plasma samples from 73 patients with MS (therapy-free for at least 90 days) and 88 healthy controls (HC) were analyzed by 1H-NMR spectroscopy. Data analysis was conducted with principal components analysis followed by a supervised analysis (orthogonal partial least squares discriminant analysis [OPLS-DA]). The metabolites were identified and quantified using Chenomx software, and the receiver operating characteristic (ROC) curves were calculated. Results: The model obtained with the OPLS-DA identified predictive metabolic differences between the patients with MS and HC (R2X = 0.615, R2Y = 0.619, Q2 = 0.476; p < 0.001). The differential metabolites included glucose, 5-OH-tryptophan, and tryptophan, which were lower in the MS group, and 3-OH-butyrate, acetoacetate, acetone, alanine, and choline, which were higher in the MS group. The suitability of the model was evaluated using an external set of samples. The values returned by the model were used to build the corresponding ROC curve (area under the curve of 0.98). Conclusion: NMR metabolomic analysis was able to discriminate different metabolic profiles in patients with MS compared with HC. With the exception of choline, the main metabolic changes could be connected to 2 different metabolic pathways: tryptophan metabolism and energy metabolism. Metabolomics appears to represent a promising noninvasive approach for the study of MS. PMID:26740964

  2. Application of 1H NMR for the characterisation of cocoa beans of different geographical origins and fermentation levels.

    PubMed

    Caligiani, Augusta; Palla, Luigi; Acquotti, Domenico; Marseglia, Angela; Palla, Gerardo

    2014-08-15

    This study reports for the first time the use of (1)H NMR technique combined with chemometrics to study the metabolic profile of cocoa (Theobroma cacao L.) beans of different varieties, origin and fermentation levels. Results of PCA applied to cocoa bean (1)H NMR dataset showed that the main factor influencing the cocoa bean metabolic profile is the fermentation level. In fact well fermented brown beans form a group clearly separated from unfermented, slaty, and underfermented, violet, beans, independently of the variety or geographical origin. Considering only well fermented beans, the metabolic profile obtained by (1)H NMR permitted to discriminate between some classes of samples. The National cocoa of Ecuador, known as Arriba, showed the most peculiar characteristics, while the samples coming from the African region showed some similar traits. The dataset obtained, representative of all the classes of soluble compounds of cocoa, was therefore useful to characterise fermented cocoa beans as a function of their origin and fermentation level.

  3. Fatty acids profile of Sacha Inchi oil and blends by 1H NMR and GC-FID.

    PubMed

    Vicente, Juarez; de Carvalho, Mario Geraldo; Garcia-Rojas, Edwin E

    2015-08-15

    This study aimed at the characterization of blends of Sacha Inchi oil (SIO) with different ratios of SO (soybean oil) and CO (corn oil) by nuclear magnetic resonance ((1)H NMR), compared with the data obtained by gas chromatography with a flame ionization detector (GC-FID). The (1)H NMR and GC-FID data from different ratios of SIO were adjusted by a second order polynomial equation. The two techniques were highly correlated (R(2) values ranged from 0.995 to 0.999), revealing that (1)H NMR is an efficient methodology for the quantification of omega-3 fatty acids in oils rich in omega-6 fatty acids or vice versa such as SO and CO and, on the other hand, can be used to quantify ω-6 in oils rich in ω-3, such as SIO.

  4. Dipolar cross-relaxation modulates signal amplitudes in the 1H NMR spectrum of hyperpolarized [ 13C]formate

    NASA Astrophysics Data System (ADS)

    Merritt, Matthew E.; Harrison, Crystal; Mander, William; Malloy, Craig R.; Dean Sherry, A.

    2007-12-01

    The asymmetry in the doublet of a spin coupled to hyperpolarized 13C has been used previously to measure the initial polarization of 13C. We tested the hypothesis that a single observation of the 1H NMR spectrum of hyperpolarized 13C formate monitors 13C polarization. Depending on the microwave frequency during the polarization process, in-phase or out-of-phase doublets were observed in the 1H NMR spectrum. Even in this simple two-spin system, 13C polarization was not reflected in the relative area of the JCH doublet components due to strong heteronuclear cross-relaxation. The Solomon equations were used to model the proton signal as a function of time after polarization and to estimate 13C polarization from the 1H NMR spectra.

  5. 1H NMR determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental and biological samples.

    PubMed

    Moura, Sidnei; Ultramari, Mariah de Almeida; de Paula, Daniela Mendes Louzada; Yonamine, Mauricio; Pinto, Ernani

    2009-04-01

    A nuclear magnetic resonance (1H NMR) method for the determination of beta-N-methylamino-L-alanine (L-BMAA) in environmental aqueous samples was developed and validated. L-BMAA is a neurotoxic modified amino acid that can be produced by cyanobacteria in aqueous environments. This toxin was extracted from samples by means of solid-phase extraction (SPE) and identified and quantified by 1H NMR without further derivatization steps. The lower limit of quantification (LLOQ) was 5 microg/mL. Good inter and intra-assay precision was also observed (relative standard deviation <8.5%) with the use of 4-nitro-DL-phenylalanine as an internal standard (IS). This method of 1H NMR analysis is not time consuming and can be readily utilized to monitor L-BMAA and confirm its presence in environmental and biological samples.

  6. Combination of 1H NMR and chemometrics to discriminate manuka honey from other floral honey types from Oceania.

    PubMed

    Spiteri, Marc; Rogers, Karyne M; Jamin, Eric; Thomas, Freddy; Guyader, Sophie; Lees, Michèle; Rutledge, Douglas N

    2017-02-15

    Manuka honey is a product produced essentially in New Zealand, and has been widely recognised for its antibacterial properties and specific taste. In this study, 264 honeys from New Zealand and Australia were analysed using proton NMR spectroscopy coupled with chemometrics. Known manuka markers, methylglyoxal and dihydroxyacetone, have been characterised and quantified, together with a new NMR marker, identified as being leptosperin. Manuka honey profiling using 1H NMR is shown to be a possible alternative to chromatography with the added advantage that it can measure methylglyoxal (MGO), dihydroxyacetone (DHA) and leptosperin simultaneously. By combining the information from these three markers, we established a model to estimate the proportion of manuka in a given honey. Markers of other botanical origins were also identified, which makes 1H NMR a convenient and efficient tool, complementary to pollen analysis, to control the botanical origin of Oceania honeys.

  7. Probing Structure Property Relationships in Complex Engineering Silicones by 1H NMR

    SciTech Connect

    Chinn, S C; Gjersing, E L; Maxwell, R S; Eastwood, E; Bowen, D; Stephens, T

    2006-07-14

    It is generally accepted that the properties of polymeric materials are controlled by the network structure and the reactions by which they have been constructed. These properties include the bulk moduli at creation, but also the properties as a function of age during use. In order to interpret mechanical properties and predict the time dependent changes in these properties, detailed knowledge of the effect of structural changes must be obtained. The degree and type of crosslinking, the molecular weight between crosslinks, the number of elastically ineffective chains (loops, dangling chain ends, sol-fraction) must be characterized. A number of theoretical and experimental efforts have been reported in the last few years on model networks prepared by endlinking reactions and the relationships of those structures with the ultimate mechanical properties. A range of experimental methods have been used to investigate structure including rheometric, scattering, infrared, {sup 29}Si MAS and CPMAS, {sup 1}H relaxation measurements, and recently {sup 1}H multiple quantum methods. Characterization of the growth of multiple quantum coherences have recently been shown to provide detailed insight into silicone network structure by the ability to selective probe the individual components of the polymer network, such as the polymer-filler interface or network chains. We have employed recently developed MQ methods to investigate the structure-property relationships in a series of complex, endlinked filled-PDMS blends. Here, a systematic study of the relationship between the molecular formulation, as dictated by the amount and type of crosslinks present and by the remaining network chains, and the segmental dynamics as observed by MQ NMR was performed.

  8. Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens.

    PubMed

    Liu, Guorui; Wu, Jun; Si, Jianyong; Wang, Junmei; Yang, Meihua

    2008-03-01

    Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.

  9. The influence of sulfur configuration in (1) H NMR chemical shifts of diasteromeric five-membered cyclic sulfites.

    PubMed

    Obregón-Mendoza, Marco A; Sánchez-Castellanos, Mariano; Cuevas, Gabriel; Gnecco, Dino; Cassani, Julia; Poveda-Jaramillo, Juan C; Reynolds, William F; Enríquez, Raúl G

    2017-03-01

    The effect of the stereochemistry of the sulfur atom on (1) H chemical shifts of the diasteromeric pair of cyclic sulfites of 4-[methoxy(4-nitrophenyl)methyl]-5-phenyl-1,3,2-dioxathiolan-2-oxide was investigated. The complete (1) H and (13) C NMR spectral assignment was achieved by the use of one-dimensional and two-dimensional NMR techniques in combination with X-ray data. A correlation of experimental data with theoretical calculations of chemical shift tensors using density functional theory and topological theory of atoms in molecules was made. Copyright © 2016 John Wiley & Sons, Ltd.

  10. UV-Vis as quantification tool for solubilized lignin following a single-shot steam process.

    PubMed

    Lee, Roland A; Bédard, Charles; Berberi, Véronique; Beauchet, Romain; Lavoie, Jean-Michel

    2013-09-01

    In this short communication, UV/Vis was used as an analytical tool for the quantification of lignin concentrations in aqueous mediums. A significant correlation was determined between absorbance and concentration of lignin in solution. For this study, lignin was produced from different types of biomasses (willow, aspen, softwood, canary grass and hemp) using steam processes. Quantification was performed at 212, 225, 237, 270, 280 and 287 nm. UV-Vis quantification of lignin was found suitable for different types of biomass making this a timesaving analytical system that could lead to uses as Process Analytical Tool (PAT) in biorefineries utilizing steam processes or comparable approaches.

  11. Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Zhengwei; Jiang, Jia Qian

    2012-07-01

    A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

  12. 1H-NMR metabolite profiles of different strains of Plasmodium falciparum

    PubMed Central

    Teng, Rongwei; Lehane, Adele M.; Winterberg, Markus; Shafik, Sarah H.; Summers, Robert L.; Martin, Rowena E.; van Schalkwyk, Donelly A.; Junankar, Pauline R.; Kirk, Kiaran

    2014-01-01

    Although efforts to understand the basis for inter-strain phenotypic variation in the most virulent malaria species, Plasmodium falciparum, have benefited from advances in genomic technologies, there have to date been few metabolomic studies of this parasite. Using 1H-NMR spectroscopy, we have compared the metabolite profiles of red blood cells infected with different P. falciparum strains. These included both chloroquine-sensitive and chloroquine-resistant strains, as well as transfectant lines engineered to express different isoforms of the chloroquine-resistance-conferring pfcrt (P. falciparum chloroquine resistance transporter). Our analyses revealed strain-specific differences in a range of metabolites. There was marked variation in the levels of the membrane precursors choline and phosphocholine, with some strains having >30-fold higher choline levels and >5-fold higher phosphocholine levels than others. Chloroquine-resistant strains showed elevated levels of a number of amino acids relative to chloroquine-sensitive strains, including an approximately 2-fold increase in aspartate levels. The elevation in amino acid levels was attributable to mutations in pfcrt. Pfcrt-linked differences in amino acid abundance were confirmed using alternate extraction and detection (HPLC) methods. Mutations acquired to withstand chloroquine exposure therefore give rise to significant biochemical alterations in the parasite. PMID:25405893

  13. Quantification of acesulfame potassium in processed foods by quantitative 1H NMR.

    PubMed

    Ohtsuki, Takashi; Sato, Kyoko; Abe, Yutaka; Sugimoto, Naoki; Akiyama, Hiroshi

    2015-01-01

    Acesulfame potassium (AceK), a high-intensity and non-caloric artificial sweetener, is used in various processed foods as a food additive. In this study, we established and validated a method for determining the AceK content in various processed foods by solvent extraction and quantitative (1)H NMR, using a certified reference material as the internal standard. In the recovery test, the proposed method gave satisfactory recoveries (88.4-99.6%) and repeatabilities (0.6-5.6%) for various processed foods. The limit of quantification was confirmed as 0.13 g kg(-1), which was sufficiently low for the purposes of monitoring AceK levels. In the analysis of commercially processed foods containing AceK, all AceK contents determined by the proposed method were in good agreement with those obtained by a conventional method based on dialysis and HPLC. Moreover, this method can achieve rapid quantification and yields analytical data with traceability to the International System of Units (SI) without the need for an authentic analyte standard. Therefore, the proposed method is a useful and practical tool for the determination of AceK in processed foods.

  14. Biochemical effects of venlafaxine on astrocytes as revealed by (1)H NMR-based metabolic profiling.

    PubMed

    Sun, Lu; Fang, Liang; Lian, Bin; Xia, Jin-Jun; Zhou, Chan-Juan; Wang, Ling; Mao, Qiang; Wang, Xin-Fa; Gong, Xue; Liang, Zi-Hong; Bai, Shun-Jie; Liao, Li; Wu, Yu; Xie, Peng

    2017-01-31

    As a serotonin-norepinephrine reuptake inhibitor [SNRI], venlafaxine is one of the most commonly prescribed clinical antidepressants, with a broad range of antidepressant effects. Accumulating evidence shows that venlafaxine may target astrocytes to exert its antidepressant activity, although the underlying pharmacological mechanisms remained largely unknown. Here, we used a (1)H nuclear magnetic resonance (NMR)-based metabonomics method coupled with multivariate statistical analysis to characterize the metabolic profiling of astrocytes treated with venlafaxine to explore the potential mechanism of its antidepressant effect. In total, 31 differential metabolites involved in energy, amino acid and lipid metabolism were identified. Ingenuity pathway analysis was used to identify the predicted pathways and biological functions with venlafaxine and fluoxetine. The most significantly altered network was "amino acid metabolism, cellular growth and proliferation", with a score above 20. Certain metabolites (lysine, tyrosine, glutamate, methionine, ethanolamine, fructose-6-phosphate, and phosphorylethanolamine) are involved in and play a central role in this network. Collectively, the biological effects of venlafaxine on astrocytes provide us with the further understanding of the mechanisms by which venlafaxine treats major depressive disorder.

  15. Tissue metabolic profiling of lymph node metastasis of colorectal cancer assessed by 1H NMR.

    PubMed

    Zhang, Hailong; Qiao, Liang; Li, Xiaopeng; Wan, Yang; Yang, Li; Wang, Huijuan

    2016-12-01

    Lymph node metastasis is a decisive prognostic and therapeutic staging factor for colorectal cancer (CRC), which is one of the most prevalent types of cancer and a malignant tumor. The metabolic profiling of tissue samples from a large cohort of lymph node non‑metastatic CRC patients (n=73), lymph node metastatic CRC patients (n=52) and normal controls (n=41) was performed using 1H nuclear magnetic resonance (NMR) together with multivariate statistical analyses. Excellent separation was obtained between CRC patients and normal controls, and CRC patients were also perfectly classified according to lymph node metastasis. Forty‑two distinguishing metabolites were identified, which revealed disturbance of glycolysis, glutaminolysis, fatty acid metabolism, choline metabolism and amino acids, suggesting that cellular functions in energy production, macromolecular synthesis, oxidative stress and immune escape of cancer cells are affected in CRC. In total, 10 tissue metabolites were significantly disturbed between non‑metastatic and metastatic CRC patients. The present study firstly staged CRC patients by lymph node metastasis by metabolomic approach. The identified metabolites may be associated with the neoplasia, invasion and metastasis of the tumor. The results suggest the promising application of these metabolites in clinical therapy, and further understanding of the related mechanism warrants further investigation.

  16. Resolution Improvements in in Vivo1H NMR Spectra with Increased Magnetic Field Strength

    NASA Astrophysics Data System (ADS)

    Gruetter, Rolf; Weisdorf, Sally A.; Rajanayagan, Vasantham; Terpstra, Melissa; Merkle, Hellmut; Truwit, Charles L.; Garwood, Michael; Nyberg, Scott L.; Ugurbil, Kâmil

    1998-11-01

    The measurement of cerebral metabolites using highly homologous localization techniques and similar shimming methods was performed in the human brain at 1.5 and 4 T as well as in the dog and rat brain at 9.4 T. In rat brain, improved resolution was achieved by shimming all first- and second-order shim coils using a fully adiabatic FASTMAP sequence. The spectra showed a clear improvement in spectral resolution for all metabolite resonances with increased field strength. Changes in cerebral glutamine content were clearly observed at 4 T compared to 1.5 T in patients with hepatic encephalopathy. At 9.4 T, glutamine H4 at 2.46 ppm was fully resolved from glutamate H4 at 2.37 ppm, as was the potential resonance from γ-amino-butyric acid at 2.30 ppm and N-acetyl-aspartyl-glutamate at 2.05 ppm. Singlet linewidths were found to be as low as 6 Hz (0.015 ppm) at 9.4 T, indicating a substantial decrease in ppm linewidth with field strength. Furthermore, the methylene peak of creatine was partially resolved from phosphocreatine, indicating a close to 1:1 relationship in gray matter. We conclude that increasing the magnetic field strength increases spectral resolution also for1H NMR, which can lead to more than linear sensitivity gains.

  17. Relativistic force field: parametric computations of proton-proton coupling constants in (1)H NMR spectra.

    PubMed

    Kutateladze, Andrei G; Mukhina, Olga A

    2014-09-05

    Spin-spin coupling constants in (1)H NMR carry a wealth of structural information and offer a powerful tool for deciphering molecular structures. However, accurate ab initio or DFT calculations of spin-spin coupling constants have been very challenging and expensive. Scaling of (easy) Fermi contacts, fc, especially in the context of recent findings by Bally and Rablen (Bally, T.; Rablen, P. R. J. Org. Chem. 2011, 76, 4818), offers a framework for achieving practical evaluation of spin-spin coupling constants. We report a faster and more precise parametrization approach utilizing a new basis set for hydrogen atoms optimized in conjunction with (i) inexpensive B3LYP/6-31G(d) molecular geometries, (ii) inexpensive 4-31G basis set for carbon atoms in fc calculations, and (iii) individual parametrization for different atom types/hybridizations, not unlike a force field in molecular mechanics, but designed for the fc's. With the training set of 608 experimental constants we achieved rmsd <0.19 Hz. The methodology performs very well as we illustrate with a set of complex organic natural products, including strychnine (rmsd 0.19 Hz), morphine (rmsd 0.24 Hz), etc. This precision is achieved with much shorter computational times: accurate spin-spin coupling constants for the two conformers of strychnine were computed in parallel on two 16-core nodes of a Linux cluster within 10 min.

  18. The (1)H NMR structure of bovine Pb(2+)-osteocalcin and implications for lead toxicity.

    PubMed

    Dowd, T L; Li, L; Gundberg, C M

    2008-11-01

    Structural information on the effect of Pb(2+) on proteins under physiologically relevant conditions is largely unknown. We have previously shown that low levels of lead increased the amount of osteocalcin bound to hydroxyapatite (BBA 1535:153). This suggested that lead induced a more compact structure in the protein. We have determined the 3D structure of Pb(2+)-osteocalcin (49 amino acids), a bone protein from a target tissue, using (1)H 2D NMR techniques. Lead, at a stoichiometry of only 1:1, induced a similar fold in the protein as that induced by Ca(2+) at a stoichiometry of 3:1. The structure consisted of an unstructured N-terminus and an ordered C-terminal consisting of a hydrophobic core (residues 16-49). The genetic algorithm-molecular dynamics simulation predicted the lead ion was coordinated by the Gla 24 and Gla 21 residues. It is proposed that mineral binding occurs via uncoordinated Gla oxygen ions binding to calcium in hydroxyapatite. A comparison of Pb(2+)- and Ca(2+)-osteocalcin suggests Pb(2+), at a lower stoichiometry, may induce similar conformational changes in proteins and subsequent molecular processes normally controlled by calcium alone. This may contribute to a molecular mechanism of lead toxicity for calcium binding proteins. Lead exposure may alter the amount of mineral bound osteocalcin and contribute to abnormal bone remodeling.

  19. Polypharmacotherapy in rheumatology: 1H NMR analysis of binding of phenylbutazone and methotrexate to serum albumin

    NASA Astrophysics Data System (ADS)

    Maciążek-Jurczyk, M.; Sułkowska, A.; Równicka-Zubik, J.; Bojko, B.; Szkudlarek-Haśnik, A.; Knopik, M.; Sułkowski, W. W.

    2011-05-01

    The influence of phenylbutazone (Phe) and methotrexate (MTX) on binding of MTX and Phe to human (HSA) and bovine (BSA) serum albumin in the low-affinity binding sites is investigated. The strength and kind of interactions between serum albumin (SA) and drugs used in combination therapy were found using 1H NMR spectroscopy. A stoichiometric molar ratios for Phe-SA and MTX-SA complexes are 36:1 and 31:1, respectively. It appeared these molar ratios are higher for the ternary systems than it were in the binary ones. The presence of the additional drug (MTX or Phe) causes the increase of an affinity of albumin towards Phe and MTX. It was found that the aliphatic groups of MTX are more resistant to the influence of Phe on the MTX-SA complex than the aromatic rings. The results showed the important impact of another drug (MTX or Phe) on the affinity of SA towards Phe and MTX in the low-affinity binding sites. This work is a subsequent part of the spectroscopic study on Phe-MTX-SA interactions (Maciążek-Jurczyk, 2009 [1]).

  20. Enantioseparation of cetirizine by chromatographic methods and discrimination by 1H-NMR.

    PubMed

    Taha, Elham A; Salama, Nahla N; Wang, Shudong

    2009-03-01

    Cetirizine is an antihistaminic drug used to prevent and treat allergic conditions. It is currently marketed as a racemate. The H1-antagonist activity of cetirizine is primarily due to (R)-levocetirizine. This has led to the introduction of (R)-levocetirizine into clinical practice, and the chiral switching is expected to be more selective and safer. The present work represents three methods for the analysis and chiral discrimination of cetirizine. The first method was based on the enantioseparation of cetirizine on silica gel TLC plates using different chiral selectors as mobile phase additives. The mobile phase enabling successful resolution was acetonitrile-water 17: 3, (v/v) containing 1 mM of chiral selector, namely hydroxypropyl-beta-cyclodextrin, chondroitin sulphate or vancomycin hydrochloride. The second method was a validated high performance liquid chromatography (HPLC), based on stereoselective separation of cetirizine and quantitative determination of its eutomer (R)-levocetirizine on a monolithic C18 column using hydroxypropyl-beta-cyclodextrin as a chiral mobile phase additive. The resolved peaks of (R)-levocetirizine and (S)-dextrocetirizine were confirmed by further mass spectrometry. The third method used a (1)H-NMR technique to characterize cetirizine and (R)-levocetirizine. These methods are selective and accurate, and can be easily applied for chiral discrimination and determination of cetirizine in drug substance and drug product in quality control laboratory. Moreover, chiral purity testing of (R)-levocetirizine can also be monitored by the chromatographic methods.

  1. 1H NMR Spectroscopy and MVA Analysis of Diplodus sargus Eating the Exotic Pest Caulerpa cylindracea

    PubMed Central

    De Pascali, Sandra A.; Del Coco, Laura; Felline, Serena; Mollo, Ernesto; Terlizzi, Antonio; Fanizzi, Francesco P.

    2015-01-01

    The green alga Caulerpa cylindracea is a non-autochthonous and invasive species that is severely affecting the native communities in the Mediterranean Sea. Recent researches show that the native edible fish Diplodus sargus actively feeds on this alga and cellular and physiological alterations have been related to the novel alimentary habits. The complex effects of such a trophic exposure to the invasive pest are still poorly understood. Here we report on the metabolic profiles of plasma from D. sargus individuals exposed to C. cylindracea along the southern Italian coast, using 1H NMR spectroscopy and multivariate analysis (Principal Component Analysis, PCA, Orthogonal Partial Least Square, PLS, and Orthogonal Partial Least Square Discriminant Analysis, OPLS-DA). Fish were sampled in two seasonal periods from three different locations, each characterized by a different degree of algal abundance. The levels of the algal bisindole alkaloid caulerpin, which is accumulated in the fish tissues, was used as an indicator of the trophic exposure to the seaweed and related to the plasma metabolic profiles. The profiles appeared clearly influenced by the sampling period beside the content of caulerpin, while the analyses also supported a moderate alteration of lipid and choline metabolism related to the Caulerpa-based diet. PMID:26058009

  2. 1H NMR spectra of humic and fulvic acids and their peracetic oxidation products

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Interesse, F. S.; Cassidei, L.; Sciacovelli, O.

    1980-04-01

    1H NMR spectra of humic (HA) and fulvic (FA) acids and their oxidative degradation products are reported. The HA shows the presence of -( CH2) n - CH3 ( n > 6) chemical fragments belonging to n-alkanes and/or n-fatty acids physically adsorbed onto the macromolecule structure. These fragments are absent in the FA fraction. Both humic fractions reveal the presence of similar amounts of aromatic protons which partly undergo exchange phenomena. The importance of this experimental observation is discussed. Oxidative degradation seems to cause partial cleavage of aromatic rings, more pronounced in the FA than in the HA. The degraded FA shows a higher total acidity and a higher phenolic OH content than the degraded HA. Both degraded fractions display some sharp singlet signals at 1.9 and 3.9 ppm arising from protons belonging to repetitive chemical fragments probably formed during the oxidation reaction. Tentative assignments of these signals are given. A general analysis of the HA and FA degraded spectra seems to indicate that the chemical fragments which undergo peracetic oxidation are substantially similar. The extent of oxidation of the two humic fractions is different. The HA degradation products reveal the presence of oligomeric structures, whereas the degraded FA appears less resistant to the oxidizing agent.

  3. Determination of glucan phosphorylation using heteronuclear 1H, 13C double and 1H, 13C, 31P triple-resonance NMR spectra.

    PubMed

    Schmieder, Peter; Nitschke, Felix; Steup, Martin; Mallow, Keven; Specker, Edgar

    2013-10-01

    Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear (1) H,(13) C and (1) H,(13) C,(31) P techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples.

  4. Using magnetic coupling to implement 1H, 19F, 13C experiments in routine high resolution NMR probes

    NASA Astrophysics Data System (ADS)

    Bowyer, Paul; Finnigan, Jim; Marsden, Brian; Taber, Bob; Zens, Albert

    2015-12-01

    We report in this paper the design of 1H, 19F, 13C circuitry using magnetic coupling which can do on demand experiments where one of the three nuclei is observed and the other two are decoupled. The implementation of this circuitry in routine NMR probes is compared with capacitive coupling methods where it was found that by using magnetic coupling the performance of the routine NMR probe was not impacted by the addition of this circuitry. It is surmised that using this type of circuitry would be highly desirable for those chemists doing routine 19F NMR.

  5. Complete assignments of 1H and 13C NMR data for seven arylnaphthalide lignans from Justicia procumbens.

    PubMed

    Yang, Meihua; Wu, Jun; Cheng, Fan; Zhou, Yuan

    2006-07-01

    Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.

  6. Measurements of intracellular volumes by 59Co and 2H/1H NMR and their physiological applications.

    PubMed

    Askenasy, Nadir; Navon, Gil

    2005-04-01

    Determination of the intracellular water volumes using NMR spectroscopy was performed using the NMR-visible nuclei: 59Co and 2H or 1H. Accurate measurement of intracellular water in cell suspensions and perfused organs is an important physiological parameter in the context of electrolyte homeostasis and energy metabolism, in particular when these parameters are monitored by non-invasive NMR spectroscopy. Furthermore, repeated or continuous monitoring of intracellular water provided significant insights into the physiology of cardiac muscle and sarcolemmal membrane permeability and integrity.

  7. Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Asiri, Abdullah M.; Kurt, Mustafa

    2014-01-01

    The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H⋯O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed.

  8. Quantitative and qualitative 1H, 13C, and 15N NMR spectroscopic investigation of the urea-formaldehyde resin synthesis.

    PubMed

    Steinhof, Oliver; Kibrik, Éléonore J; Scherr, Günter; Hasse, Hans

    2014-04-01

    Urea-formaldehyde resins are bulk products of the chemical industry. Their synthesis involves a complex reaction network. The present work contributes to its elucidation by presenting results from detailed NMR spectroscopic studies with different methods. Besides (1)H NMR and (13)C NMR, (15)N NMR spectroscopy is also applied. (15)N-enriched urea was used for the investigations. A detailed NMR signal assignment and a model of the reaction network of the hydroxymethylation step of the synthesis are presented. Because of its higher spectral dispersion and the fact that all key reactions directly involve the nitrogen centers, (15)N NMR provides a much larger amount of detail than do (1)H and (13)C NMR spectroscopy. Symmetric and asymmetric dimethylol urea can be clearly distinguished and separated from monomethylol urea, trimethylol urea, and methylene-bridged urea. The existence of hemiformals of methylol urea is confirmed. 1,3,5-Oxadiazinan-4-on (uron) and its derivatives were not found in the reaction mixtures investigated here but were prepared via alternative routes. The molar ratios of formaldehyde to urea were 1, 2, and 4, the pH values 7.5 and 8.5, and the reaction temperature 60 °C.

  9. Complete assignment of the (1)H and (13)C NMR spectra of cis and trans isonucleoside derivatives of purine with a tetrahydropyran ring.

    PubMed

    Besada, Pedro; Costas, Tamara; Terán, Carmen

    2010-06-01

    (1)H and (13)C NMR chemical shifts of cis and trans isonucleoside analogues of purine in which the furanose moiety is substituted by a tetrahydropyran ring were completely assigned using one- and two-dimensional NMR experiments that include NOE, DEPT, COSY and HSQC. The significant (1)H and (13)C NMR signals differentiating between the cis and trans stereoisomers were compared.

  10. Studies of Secondary Melanoma on C57BL/6J Mouse Liver Using 1H NMR Metabolomics

    SciTech Connect

    Feng, Ju; Isern, Nancy G.; Burton, Sarah D.; Hu, Jian Z.

    2013-10-31

    NMR metabolomics, consisting of solid state high resolution (hr) magic angle spinning (MAS) 1H NMR (1H hr-MAS), liquid state high resolution 1H-NMR, and principal components analysis (PCA) has been used to study secondary metastatic B16-F10 melanoma in C57BL/6J mouse liver . The melanoma group can be differentiated from its control group by PCA analysis of the absolute concentrations or by the absolute peak intensities of metabolites from either 1H hr-MAS NMR data on intact liver tissues or liquid state 1H-NMR spectra on liver tissue extracts. In particular, we found that the absolute concentrations of alanine, glutamate, creatine, creatinine, fumarate and cholesterol are elevated in the melanoma group as compared to controls, while the absolute concentrations of succinate, glycine, glucose, and the family of linear lipids including long chain fatty acids, total choline and acylglycerol are decreased. The ratio of glycerophosphocholine to phosphocholine is increased by about 1.5 fold in the melanoma group, while the absolute concentration of total choline is actually lower in melanoma mice. These results suggest the following picture in secondary melanoma metastasis: Linear lipid levels are decreased by beta oxidation in the melanoma group, which contributes to an increase in the synthesis of cholesterol, and also provides an energy source input for TCA cycle. These findings suggest a link between lipid oxidation, the TCA cycle and the hypoxia-inducible factors (HIF) signal pathway in tumor metastases. Thus this study indicates that the metabolic profile derived from NMR analysis can provide a valuable bio-signature of malignancy and cell hypoxia in metastatic melanoma.

  11. Robust algorithms for automated chemical shift calibration of 1D 1H NMR spectra of blood serum.

    PubMed

    Pearce, Jake T M; Athersuch, Toby J; Ebbels, Timothy M D; Lindon, John C; Nicholson, Jeremy K; Keun, Hector C

    2008-09-15

    In biofluid NMR spectroscopy, the frequency of each resonance is typically calibrated by addition of a reference compound such as 3-(trimethylsilyl)-propionic acid- d 4 (TSP) to the sample. However biofluids such as serum cannot be referenced to TSP, due to shifts resonance caused by binding to macromolecules in solution. In order to overcome this limitation we have developed algorithms, based on analysis of derivative spectra, to locate and calibrate (1)H NMR spectra to the alpha-glucose anomeric doublet. We successfully used these algorithms to calibrate 77 serum (1)H NMR spectra and demonstrate the greater reproducibility of the calculated chemical-shift corrections ( r = 0.97) than those generated by manual alignment ( r = 0.8-0.88). Hence we show that these algorithms provide robust and reproducible methods of calibrating (1)H NMR of serum, plasma, or any biofluid in which glucose is abundant. Precise automated calibration of complex biofluid NMR spectra is an important tool in large-scale metabonomic or metabolomic studies, where hundreds or even thousands of spectra may be analyzed in high-resolution by pattern recognition analysis.

  12. 1H and 13C NMR signal assignments of a novel Baeyer-Villiger originated diterpene lactone.

    PubMed

    Vieira, Henriete S; Takahashi, Jacqueline A; Gunatilaka, A A Leslie; Boaventura, Maria Amélia D

    2006-02-01

    A highly rearranged novel dilactone was the single product isolated from Baeyer-Villiger oxidation of a norketone prepared from grandiflorenic acid, a natural kaurane diterpene. The complete 1H and 13C NMR assignment is presented for this novel compound that showed discrete in vitro antibacterial activity.

  13. 1H, 13C and 15N NMR assignments of a calcium-binding protein from Entamoeba histolytica.

    PubMed

    Verma, Deepshikha; Bhattacharya, Alok; Chary, Kandala V R

    2016-04-01

    We report almost complete sequence specific (1)H, (13)C and (15)N NMR assignments of a 150-residue long calmodulin-like calcium-binding protein from Entamoeba histolytica (EhCaBP6), as a prelude to its structural and functional characterization.

  14. LC-MS and 1H NMR as an improved dereplication tool to identify antifungal diterpenoids from Sagittaria latifolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A dereplication strategy using a combination of liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy (1H NMR) to facilitate compound identification towards antifungal natural product discovery is presented. This analytical approach takes advantage of th...

  15. Quality evaluation and prediction of Citrullus lanatus by 1H NMR-based metabolomics and multivariate analysis.

    PubMed

    Tarachiwin, Lucksanaporn; Masako, Osawa; Fukusaki, Eiichiro

    2008-07-23

    (1)H NMR spectrometry in combination with multivariate analysis was considered to provide greater information on quality assessment over an ordinary sensory testing method due to its high reliability and high accuracy. The sensory quality evaluation of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) was carried out by means of (1)H NMR-based metabolomics. Multivariate analyses by partial least-squares projections to latent structures-discrimination analysis (PLS-DA) and PLS-regression offered extensive information for quality differentiation and quality evaluation, respectively. The impact of watermelon and rootstock cultivars on the sensory qualities of watermelon was determined on the basis of (1)H NMR metabolic fingerprinting and profiling. The significant metabolites contributing to the discrimination were also identified. A multivariate calibration model was successfully constructed by PLS-regression with extremely high reliability and accuracy. Thus, (1)H NMR-based metabolomics with multivariate analysis was considered to be one of the most suitable complementary techniques that could be applied to assess and predict the sensory quality of watermelons and other horticultural plants.

  16. Application of (1)h NMR profiling to assess seed metabolomic diversity. A case study on a soybean era population.

    PubMed

    Harrigan, George G; Skogerson, Kirsten; MacIsaac, Susan; Bickel, Anna; Perez, Tim; Li, Xin

    2015-05-13

    (1)H NMR spectroscopy offers advantages in metabolite quantitation and platform robustness when applied in food metabolomics studies. This paper provides a (1)H NMR-based assessment of seed metabolomic diversity in conventional and glyphosate-resistant genetically modified (GM) soybean from a genetic lineage representing ∼35 years of breeding and differing yield potential. (1)H NMR profiling of harvested seed allowed quantitation of 27 metabolites, including free amino acids, sugars, and organic acids, as well as choline, O-acetylcholine, dimethylamine, trigonelline, and p-cresol. Data were analyzed by canonical discriminant analysis (CDA) and principal variance component analysis (PVCA). Results demonstrated that (1)H NMR spectroscopy was effective in highlighting variation in metabolite levels in the genetically diverse sample set presented. The results also confirmed that metabolite variability is influenced by selective breeding and environment, but not genetic modification. Therefore, metabolite variability is an integral part of crop improvement that has occurred for decades and is associated with a history of safe use.

  17. Extraction and [superscript 1]H NMR Analysis of Fats from Convenience Foods: A Laboratory Experiment for Organic Chemistry

    ERIC Educational Resources Information Center

    Hartel, Aaron M.; Moore, Amy C.

    2014-01-01

    The extraction and analysis of fats from convenience foods (crackers, cookies, chips, candies) has been developed as an experiment for a second-year undergraduate organic chemistry laboratory course. Students gravimetrically determine the fat content per serving and then perform a [superscript 1]H NMR analysis of the recovered fat to determine the…

  18. Microscale Synthesis and (super 1)H NMR Analysis of Zn(super II) and Ni(super II) Tetraphenylporphyrins

    ERIC Educational Resources Information Center

    Saucedo, Laura; Mink, Larry M.

    2005-01-01

    A multisection undergraduate laboratory involving the microscale synthesis and spectroscopic analysis of unmetalled porphyrins and their corresponding metalloporphyins is described. The microscale synthesis involving the isolation of the metalloporphyrins as solids and their corresponding (super 1)H NMR spectra are presented.

  19. Instrumental Analysis in the High School Classroom: UV-Vis Spectroscopy

    ERIC Educational Resources Information Center

    Erhardt, Walt

    2007-01-01

    Note is presented on the standard lab from a second year chemistry course. The lab "Determining which of the Seven FD&C Food-Approved Dyes are Used in Making Green Skittles", familiarizes students with the operation of the CHEM2000 UV-Vis spectrophorometer.

  20. Instrumentation: Photodiode Array Detectors in UV-VIS Spectroscopy. Part II.

    ERIC Educational Resources Information Center

    Jones, Dianna G.

    1985-01-01

    A previous part (Analytical Chemistry; v57 n9 p1057A) discussed the theoretical aspects of diode ultraviolet-visual (UV-VIS) spectroscopy. This part describes the applications of diode arrays in analytical chemistry, also considering spectroelectrochemistry, high performance liquid chromatography (HPLC), HPLC data processing, stopped flow, and…

  1. Sequential capillary electrophoresis analysis using optically gated sample injection and UV/vis detection.

    PubMed

    Liu, Xiaoxia; Tian, Miaomiao; Camara, Mohamed Amara; Guo, Liping; Yang, Li

    2015-10-01

    We present sequential CE analysis of amino acids and L-asparaginase-catalyzed enzyme reaction, by combing the on-line derivatization, optically gated (OG) injection and commercial-available UV-Vis detection. Various experimental conditions for sequential OG-UV/vis CE analysis were investigated and optimized by analyzing a standard mixture of amino acids. High reproducibility of the sequential CE analysis was demonstrated with RSD values (n = 20) of 2.23, 2.57, and 0.70% for peak heights, peak areas, and migration times, respectively, and the LOD of 5.0 μM (for asparagine) and 2.0 μM (for aspartic acid) were obtained. With the application of the OG-UV/vis CE analysis, sequential online CE enzyme assay of L-asparaginase-catalyzed enzyme reaction was carried out by automatically and continuously monitoring the substrate consumption and the product formation every 12 s from the beginning to the end of the reaction. The Michaelis constants for the reaction were obtained and were found to be in good agreement with the results of traditional off-line enzyme assays. The study demonstrated the feasibility and reliability of integrating the OG injection with UV/vis detection for sequential online CE analysis, which could be of potential value for online monitoring various chemical reaction and bioprocesses.

  2. Quantitative classification of cryptosporidium oocysts and giardia cysts in water using UV/vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Bacon, Christina P.; Rose, J. B.; Patten, K.; Garcia-Rubio, Luis H.

    1995-05-01

    Cryptosporidium and Giardia are enteric protozoa which cause waterborne diseases. To date, the detection of these organisms in water has relied upon microscopic immunofluorescent assay technology which uses antibodies directed against the cyst and oocyst forms of the protozoa. In this paper, the uv/vis extinction spectra of aqueous dispersions of Cryptosporidium and Giardia have been studied to investigate the potential use of light scattering-spectral deconvolution techniques as a rapid method for the identification and quantification of protozoa in water. Examination of purified samples of Cryptosporidium and Giardia suggests that spectral features apparent in the short wavelength region of the uv/vis spectra contain information that may be species specific for each protozoa. The spectral characteristics, as well as the particle size analysis, determined from the same spectra, allow for the quantitative classification, identification, and possibly, the assessment of the viability of the protozoa. To further increase the sensitivity of this technique, specific antibodies direction against these organisms, labelled with FITC and rhodamine are being used. It is demonstrated that uv/vis spectroscopy provides an alternative method for the characterization of Giardia and Cryptosporidium. The simplicity and reproducibility of uv/vis spectroscopy measurements makes this technique ideally suited for the development of on-line instrumentation for the rapid detection of microorganisms in water supplies.

  3. Principal component analysis of UV-VIS-NIR transmission spectra of Moldavian matured wine distillates

    NASA Astrophysics Data System (ADS)

    Khodasevich, Mikhail A.; Trofimova, Darya V.; Nezalzova, Elena I.

    2010-09-01

    Principal component analysis of UV-VIS-NIR transmission spectra of matured wine distillates (1-40 years aged) produced by three Moldavian manufacturers allows to characterize with sufficient certainty the eleven chemical parameters of considered alcoholic beverages: contents of acetaldehyde, ethyl acetate, furfural, vanillin, syringic aldehyde and acid, etc.

  4. Principal component analysis of UV-VIS-NIR transmission spectra of Moldavian matured wine distillates

    NASA Astrophysics Data System (ADS)

    Khodasevich, Mikhail A.; Trofimova, Darya V.; Nezalzova, Elena I.

    2011-02-01

    Principal component analysis of UV-VIS-NIR transmission spectra of matured wine distillates (1-40 years aged) produced by three Moldavian manufacturers allows to characterize with sufficient certainty the eleven chemical parameters of considered alcoholic beverages: contents of acetaldehyde, ethyl acetate, furfural, vanillin, syringic aldehyde and acid, etc.

  5. A thorough study on the use of quantitative 1H NMR in Rioja red wine fermentation processes.

    PubMed

    López-Rituerto, Eva; Cabredo, Susana; López, Martina; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

    2009-03-25

    In this study, we focused our attention on monitoring the levels of important metabolites of wine during the alcoholic and malolactic fermentation processes by quantitative nuclear magnetic resonance (qNMR). Therefore, using (1)H NMR, the method allows the simultaneous quantification of ethanol, acetic, malic, lactic, and succinic acids, and the amino acids proline and alanine, besides the ratio proline/arginine through fermentation of must of grapes corresponding to the Tempranillo variety. Each (1)H NMR spectrum gives direct and visual information concerning these metabolites, and the effectiveness of each process was assessed and compared by carrying out analyses using infrared spectroscopy to ethanol and acetic acid. The quantitative data were explained with the aid of chemometric algorithms.

  6. Bonding in hard and elastic amorphous carbon nitride films investigated using 15N, 13C, and 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Gammon, W. J.; Hoatson, G. L.; Holloway, B. C.; Vold, R. L.; Reilly, A. C.

    2003-11-01

    The nitrogen bonding in hard and elastic amorphous carbon nitride (a-CNx) films is examined with 15N, 13C, and 1H nuclear magnetic resonance (NMR) spectroscopy. Films were deposited by dc magnetron sputtering, in a pure nitrogen discharge on Si(001) substrates at 300 °C. Nanoindentation tests revealed an elastic recovery of 80%, a hardness of 5 GPa, and an elastic modulus of 47 GPa. The NMR results show that nitrogen bonding in this material is consistent with sp2 hybridized nitrogen incorporated in an aromatic carbon environment. The data also indicate that the a-CNx prepared for this study has very low hydrogen content and is hydrophilic. Specifically, analysis of 15N and 13C cross polarization magic angle spinning and 1H NMR experiments suggests that water preferentially protonates nitrogen sites.

  7. Metabonomic signature analysis of cervical carcinoma and precancerous lesions in women by 1H NMR spectroscopy

    PubMed Central

    HASIM, AYSHAMGUL; ALI, MAYINUER; MAMTIMIN, BATUR; MA, JUN-QI; LI, QIAO-ZHI; ABUDULA, ABULIZI

    2012-01-01

    1H nuclear magnetic resonance (NMR)-based metabonomics has been used to characterize the metabolic profiles of cervical intraepithelial neoplasia (CIN) and cervical squamous cell carcinoma (CSCC). Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used to model the systematic variation related to patients with CIN or CSCC with healthy controls. Potential metabolic biomarkers were identified using database comparisons, and the one-way analysis of variance (ANOVA) test was used to examine the significance of the metabolites. Compared with plasma obtained from the healthy controls, plasma from patients with CIN had higher levels of very-low density lipoprotein (VLDL), acetone, unsaturated lipid and carnitine, together with lower levels of creatine, lactate, isoleucine, leucine, valine, alanine, glutamine, histidine, glycine, acetylcysteine, myo-inositol, choline and glycoprotein. Plasma from patients with CSCC had higher levels of acetate and formate, together with lower levels of creatine, lactate, isoleucine, leucine, valine, alanine, glutamine, histidine and tyrosine compared with the plasma of the healthy controls. In addition, compared with the plasma of patients with CIN, the plasma of CSCC patients had higher levels of acetate, formate, lactate, isoleucine, leucine, valine, alanine, glutamine, histidine, tyrosine, acetylcysteine, myo-inositol, glycoprotein, α-glucose and β-glucose, together with lower levels of acetone, unsaturated lipid and carnitine. Moreover, the profiles showed high feasibility and specificity by statistical analysis with OPLS-DA compared to the Thinprep cytology test (TCT) by setting the histopathological outcome as standard. The metabolic profile obtained for cervical cancer is significant, even for the precancerous disease. This suggests a systemic metabolic response to cancer, which may be used to identify potential early diagnostic biomarkers of the cancer and to establish

  8. Evaluation of 1H NMR metabolic profiling using biofluid mixture design.

    PubMed

    Athersuch, Toby J; Malik, Shahid; Weljie, Aalim; Newton, Jack; Keun, Hector C

    2013-07-16

    A strategy for evaluating the performance of quantitative spectral analysis tools in conditions that better approximate background variation in a metabonomics experiment is presented. Three different urine samples were mixed in known proportions according to a {3, 3} simplex lattice experimental design and analyzed in triplicate by 1D (1)H NMR spectroscopy. Fifty-four urinary metabolites were subsequently quantified from the sample spectra using two methods common in metabolic profiling studies: (1) targeted spectral fitting and (2) targeted spectral integration. Multivariate analysis using partial least-squares (PLS) regression showed the latent structure of the spectral set recapitulated the experimental mixture design. The goodness-of-prediction statistic (Q(2)) of each metabolite variable in a PLS model was calculated as a metric for the reliability of measurement, across the sample compositional space. Several metabolites were observed to have low Q(2) values, largely as a consequence of their spectral resonances having low s/n or strong overlap with other sample components. This strategy has the potential to allow evaluation of spectral features obtained from metabolic profiling platforms in the context of the compositional background found in real biological sample sets, which may be subject to considerable variation. We suggest that it be incorporated into metabolic profiling studies to improve the estimation of matrix effects that confound accurate metabolite measurement. This novel method provides a rational basis for exploiting information from several samples in an efficient manner and avoids the use of multiple spike-in authentic standards, which may be difficult to obtain.

  9. Detection of cerebral NAD(+) by in vivo (1)H NMR spectroscopy.

    PubMed

    de Graaf, Robin A; Behar, Kevin L

    2014-07-01

    Nicotinamide adenine dinucleotide (NAD(+)) plays a central role in cellular metabolism both as a coenzyme for electron-transfer enzymes as well as a substrate for a wide range of metabolic pathways. In the current study NAD(+) was detected on rat brain in vivo at 11.7T by 3D localized (1)H MRS of the NAD(+) nicotinamide protons in the 8.7-9.5 ppm spectral region. Avoiding water perturbation was critical to the detection of NAD(+) as strong, possibly indirect cross-relaxation between NAD(+) and water would lead to a several-fold reduction of the NAD(+) intensity in the presence of water suppression. Water perturbation was minimized through the use of localization by adiabatic spin-echo refocusing (LASER) in combination with frequency-selective excitation. The NAD(+) concentration in the rat cerebral cortex was determined at 296 ± 28 μm, which is in good agreement with recently published (31) P NMR-based results as well as results from brain extracts in vitro (355 ± 34 μm). The T1 relaxation time constants of the NAD(+) nicotinamide protons as measured by inversion recovery were 280 ± 65 and 1136 ± 122 ms in the absence and presence of water inversion, respectively. This confirms the strong interaction between NAD(+) nicotinamide and water protons as observed during water suppression. The T2 relaxation time constants of the NAD(+) nicotinamide protons were determined at 60 ± 13 ms after confounding effects of scalar coupling evolution were taken into account. The simplicity of the MR sequence together with the robustness of NAD(+) signal detection and quantification makes the presented method a convenient choice for studies on NAD(+) metabolism and function. As the method does not critically rely on magnetic field homogeneity and spectral resolution it should find immediate applications in rodents and humans even at lower magnetic fields.

  10. Selective excitation enables assignment of proton resonances and (1)H-(1)H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-21

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of (1)H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as (13)C or (15)N. In this method, after the initial preparation of proton magnetization and cross-polarization to (13)C nuclei, transverse magnetization of desired (13)C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific (13)C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of (1)H-(1)H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

  11. Selective excitation enables assignment of proton resonances and 1H-1H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-01

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of 1H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as 13C or 15N. In this method, after the initial preparation of proton magnetization and cross-polarization to 13C nuclei, transverse magnetization of desired 13C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific 13C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of 1H-1H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

  12. Selective excitation enables assignment of proton resonances and {sup 1}H-{sup 1}H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-21

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of {sup 1}H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as {sup 13}C or {sup 15}N. In this method, after the initial preparation of proton magnetization and cross-polarization to {sup 13}C nuclei, transverse magnetization of desired {sup 13}C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific {sup 13}C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of {sup 1}H-{sup 1}H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

  13. Chiral trimethylsilylated C2-symmetrical diamines as phosphorous derivatizing agents for the determination of the enantiomeric excess of chiral alcohols by 1H NMR

    PubMed Central

    Chauvin, Anne-Sophie; Alexakis, Alexandre

    2006-01-01

    The use of organophosphorus derivatising agents, prepared from C2 symmetric trimethylsilylated diamines, for the 1H NMR and 31P NMR determination of the enantiomeric composition of chiral alcohols is described. PMID:16566844

  14. 1H NMR, 13C NMR and mass spectral studies of some Schiff bases derived from 3-amino-1,2,4-triazole.

    PubMed

    Issa, Y M; Hassib, H B; Abdelaal, H E

    2009-11-01

    Heterocyclic Schiff bases derived from 3-amino-1,2,4-triazole and different substituted aromatic aldehydes are prepared and subjected to (1)H NMR, (13)C NMR and mass spectral analyses. (1)H NMR spectra in DMSO exhibit a sharp singlet within the 9.35-8.90ppm region which corresponds to the azomethine proton. The position of this signal is largely dependent on the nature of the substituents on the benzal moiety. It is observed that the shape, position and the integration value of the signal of the aromatic proton of the triazole ring ((5)C) are clearly affected by the rate of exchange, relaxation time, concentration of solution as well as the solvent used. (13)C NMR is taken as substantial support for the results reached from (1)H NMR studies. The mass spectral results are taken as a tool to confirm the structure of the investigated compounds. The base peak (100%), mostly the M-1 peak, indicates the facile loss of hydrogen radical. The fragmentation pattern of the unsubstituted Schiff base is taken as the general scheme. Differences in the other schemes result from the effect of the electronegativity of the substituents attached to the aromatic ring.

  15. A closer look at the nitrogen next door: 1H-15N NMR methods for glycosaminoglycan structural characterization

    NASA Astrophysics Data System (ADS)

    Langeslay, Derek J.; Beni, Szabolcs; Larive, Cynthia K.

    2012-03-01

    Recently, experimental conditions were presented for the detection of the N-sulfoglucosamine (GlcNS) NHSO3- or sulfamate 1H and 15N NMR resonances of the pharmaceutically and biologically important glycosaminoglycan (GAG) heparin in aqueous solution. In the present work, we explore further the applicability of nitrogen-bound proton detection to provide structural information for GAGs. Compared to the detection of 15N chemical shifts of aminosugars through long-range couplings using the IMPACT-HNMBC pulse sequence, the more sensitive two-dimensional 1H-15N HSQC-TOCSY experiments provided additional structural data. The IMPACT-HNMBC experiment remains a powerful tool as demonstrated by the spectrum measured for the unsubstituted amine of 3-O-sulfoglucosamine (GlcN(3S)), which cannot be observed with the 1H-15N HSQC-TOCSY experiment due to the fast exchange of the amino group protons with solvent. The 1H-15N HSQC-TOCSY NMR spectrum reported for the mixture of model compounds GlcNS and N-acetylglucosamine (GlcNAc) demonstrate the broad utility of this approach. Measurements for the synthetic pentasaccharide drug Arixtra® (Fondaparinux sodium) in aqueous solution illustrate the power of this NMR pulse sequence for structural characterization of highly similar N-sulfoglucosamine residues in GAG-derived oligosaccharides.

  16. Unambiguous Metabolite Identification in High-Throughput Metabolomics by Hybrid 1H-NMR/ESI-MS1 Approach

    SciTech Connect

    2016-10-18

    The invention improves accuracy of metabolite identification by combining direct infusion ESI-MS with one-dimensional 1H-NMR spectroscopy. First, we apply a standard 1H-NMR metabolite identification protocol by matching the chemical shift, J-coupling and intensity information of experimental NMR signals against the NMR signals of standard metabolites in a metabolomics reference libraries. This generates a list of candidate metabolites. The list contains both false positive and ambiguous identifications. The software tool (the invention) takes the list of candidate metabolites, generated from NMRbased metabolite identification, and then calculates, for each of the candidate metabolites, the monoisotopic mass-tocharge (m/z) ratios for each commonly observed ion, fragment and adduct feature. These are then used to assign m/z ratios in experimental ESI-MS spectra of the same sample. Detection of the signals of a given metabolite in both NMR and MS spectra resolves the ambiguities, and therefore, significantly improves the confidence of the identification.

  17. 1H-detected solid-state NMR of proteins entrapped in bioinspired silica: a new tool for biomaterials characterization

    PubMed Central

    Ravera, Enrico; Cerofolini, Linda; Martelli, Tommaso; Louka, Alexandra; Fragai, Marco; Luchinat, Claudio

    2016-01-01

    Proton-detection in solid-state NMR, enabled by high magnetic fields (>18 T) and fast magic angle spinning (>50 kHz), allows for the acquisition of traditional 1H-15N experiments on systems that are too big to be observed in solution. Among those, proteins entrapped in a bioinspired silica matrix are an attractive target that is receiving a large share of attention. We demonstrate that 1H-detected SSNMR provides a novel approach to the rapid assessment of structural integrity in proteins entrapped in bioinspired silica. PMID:27279168

  18. 1H-detected solid-state NMR of proteins entrapped in bioinspired silica: a new tool for biomaterials characterization

    NASA Astrophysics Data System (ADS)

    Ravera, Enrico; Cerofolini, Linda; Martelli, Tommaso; Louka, Alexandra; Fragai, Marco; Luchinat, Claudio

    2016-06-01

    Proton-detection in solid-state NMR, enabled by high magnetic fields (>18 T) and fast magic angle spinning (>50 kHz), allows for the acquisition of traditional 1H-15N experiments on systems that are too big to be observed in solution. Among those, proteins entrapped in a bioinspired silica matrix are an attractive target that is receiving a large share of attention. We demonstrate that 1H-detected SSNMR provides a novel approach to the rapid assessment of structural integrity in proteins entrapped in bioinspired silica.

  19. MAS (1)H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes.

    PubMed

    Mandal, Abhishek; van der Wel, Patrick C A

    2016-11-01

    The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS (1)H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (Tm). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.

  20. Diagnosis of cerebral cryptococcoma using a computerized analysis of 1H NMR spectra in an animal model.

    PubMed

    Dzendrowskyj, Theresa E; Dolenko, Brion; Sorrell, Tania C; Somorjai, Rajmund L; Malik, Richard; Mountford, Carolyn E; Himmelreich, Uwe

    2005-06-01

    Viable cryptococci load in biopsy material from an animal model of cerebral cryptococcoma were correlated with 1H NMR spectra and metabolite profiles. A statistical classification strategy was applied to distinguish among high-resolution 1H NMR spectra acquired from cryptococcomas, glioblastomas, and normal brain tissue. The overall classification accuracy was 100% when a genetic-algorithm-based optimal region selection preceded the development of linear discriminant analysis-based classifiers. The method remained robust despite differences in the microbial load of the cryptococcoma group when harvested at different time points. These results indicate the feasibility of the method for diagnosis without isolation of the pathogenic microorganism and its potential for in vivo diagnosis based on computerized analysis of magnetic resonance spectra.

  1. The origin of molecular mobility during biomass pyrolysis as revealed by in situ (1)H NMR spectroscopy.

    PubMed

    Dufour, Anthony; Castro-Diaz, Miguel; Brosse, Nicolas; Bouroukba, Mohamed; Snape, Colin

    2012-07-01

    The thermochemical conversion of lignocellulosic biomass feedstocks offers an important potential route for the production of biofuels and value-added green chemicals. Pyrolysis is the first phenomenon involved in all biomass thermochemical processes and it controls to a major extent the product composition. The composition of pyrolysis products can be affected markedly by the extent of softening that occurs. In spite of extensive work on biomass pyrolysis, the development of fluidity during the pyrolysis of biomass has not been quantified. This paper provides the first experimental investigation of proton mobility during biomass pyrolysis by in situ (1)H NMR spectroscopy. The origin of mobility is discussed for cellulose, lignin and xylan. The effect of minerals on cellulose mobility is also investigated. Interactions between polymers in the native biomass network are revealed by in situ (1)H NMR analysis.

  2. A study by (1)H NMR on the influence of some factors affecting lipid in vitro digestion.

    PubMed

    Nieva-Echevarría, Bárbara; Goicoechea, Encarnación; Manzanos, María J; Guillén, María D

    2016-11-15

    This article focuses on the impact of several experimental factors, including gastric acidification, intestinal transit time, presence of gastric lipase, sample/digestive fluids ratio, concentration and nature of the enzymes in intestinal juice, and bile concentration, on the extent of in vitro lipolysis when using a static model that simulates human digestion processes in mouth, stomach and small intestine. The study was carried out by Proton Nuclear Magnetic Resonance ((1)H NMR). This technique provides a complete molecular picture of lipolysis, evidencing for the first time, whether preferential hydrolysis of certain glycerides over others occurs. A lipolysis degree similar to that reported in vivo was reached by varying certain variables within a physiological range; among them, bile concentration was found to be crucial. The holistic view of this (1)H NMR study provides information of paramount importance to design sound in vitro digestion models to determine the bioaccessibility and bioavailability of lipophilic compounds.

  3. FT-IR and {sup 1}H NMR characterization of the products of an ethylene inverse diffusion flame

    SciTech Connect

    Santamaria, Alexander; Mondragon, Fanor; Molina, Alejandro; Marsh, Nathan D.; Eddings, Eric G.; Sarofim, Adel F.

    2006-07-15

    Knowledge of the chemical structure of young soot and its precursors is very useful in the understanding of the paths leading to soot particle inception. This paper presents analyses of the chemical functional groups, based on FT-IR and {sup 1}H NMR spectroscopy of the products obtained in an ethylene inverse diffusion flame. The trends in the data indicate that the soluble fraction of the soot becomes progressively more aromatic and less aliphatic as the height above the burner increases. Results from {sup 1}H NMR spectra of the chloroform-soluble soot samples taken at different heights above the burner corroborate the infrared results based on proton chemical shifts (Ha, H{alpha}, H{beta}, and H{gamma}). The results indicate that the aliphatic {beta} and {gamma} hydrogens suffered the most drastic reduction, while the aromatic character increased considerably with height, particularly in the first half of the flame. (author)

  4. In vitro interaction of selected phospholipid species with mercuric chloride using Fourier transform sup 1 H-NMR

    SciTech Connect

    Shinada, Masayuki; Muto, Hajime; Takizawa, Yukio )

    1991-09-01

    Many studies on the mercury toxicities have been accumulated since the outbreak of Minamata Disease.' There have been few reports on the reaction mechanisms of mercurials with phospholipids which substantially locate in biological membranes, although the interactions of nucleotides or nucleosides with mercurials have been reported. Recently, the study on the interaction of mercuric chloride (HgCl{sub 2}) with amino polar heads of model membranes containing phosphatidylserine (PS) and phosphatidylethanolamine (PE) has been reported, as the results from the fluorescence polarization analysis using 1,6-diphenyl-1,3,5-hexatriene. The authors demonstrate here the interactions of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC) with HgCl{sub 2}, using Fourier transform {sup 1}H-NMR ({sup 1}H-FT-NMR).

  5. Metabolite profiling of Clinacanthus nutans leaves extracts obtained from different drying methods by 1H NMR-based metabolomics

    NASA Astrophysics Data System (ADS)

    Hashim, Noor Haslinda Noor; Latip, Jalifah; Khatib, Alfi

    2016-11-01

    The metabolites of Clinacanthus nutans leaves extracts and their dependence on drying process were systematically characterized using 1H nuclear magnetic resonance spectroscopy (NMR) multivariate data analysis. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were able to distinguish the leaves extracts obtained from different drying methods. The identified metabolites were carbohydrates, amino acid, flavonoids and sulfur glucoside compounds. The major metabolites responsible for the separation in PLS-DA loading plots were lupeol, cycloclinacosides, betulin, cerebrosides and choline. The results showed that the combination of 1H NMR spectroscopy and multivariate data analyses could act as an efficient technique to understand the C. nutans composition and its variation.

  6. Characterizing Covalently Sidewall-Functionalized SWCNTs by using 1H NMR Spectroscopy

    PubMed Central

    Nelson, Donna J.; Kumar, Ravi

    2013-01-01

    Unambiguous evidence for covalent sidewall functionalization of single-walled carbon nanotubes (SWCNTs) has been a difficult task, especially for nanomaterials in which slight differences in functionality structure produce significant changes in molecular characteristics. Nuclear magnetic resonance (NMR) spectroscopy provides clear information about the structural skeleton of molecules attached to SWCNTs. In order to establish the generality of proton NMR as an analytical technique for characterizing covalently functionalized SWCNTs, we have obtained and analyzed proton NMR data of SWCNT-substituted benzenes across a variety of para substituents. Trends obtained for differences in proton NMR chemical shifts and the impact of o-, p-, and m-directing effects of electrophilic aromatic substituents on phenyl groups covalently bonded to SWCNTs are discussed. PMID:24009779

  7. Improving the efficiency of quantitative (1)H NMR: an innovative external standard-internal reference approach.

    PubMed

    Huang, Yande; Su, Bao-Ning; Ye, Qingmei; Palaniswamy, Venkatapuram A; Bolgar, Mark S; Raglione, Thomas V

    2014-01-01

    The classical internal standard quantitative NMR (qNMR) method determines the purity of an analyte by the determination of a solution containing the analyte and a standard. Therefore, the standard must meet the requirements of chemical compatibility and lack of resonance interference with the analyte as well as a known purity. The identification of such a standard can be time consuming and must be repeated for each analyte. In contrast, the external standard qNMR method utilizes a standard with a known purity to calibrate the NMR instrument. The external standard and the analyte are measured separately, thereby eliminating the matter of chemical compatibility and resonance interference between the standard and the analyte. However, the instrumental factors, including the quality of NMR tubes, must be kept the same. Any deviations will compromise the accuracy of the results. An innovative qNMR method reported herein utilizes an internal reference substance along with an external standard to assume the role of the standard used in the traditional internal standard qNMR method. In this new method, the internal reference substance must only be chemically compatible and be free of resonance-interference with the analyte or external standard whereas the external standard must only be of a known purity. The exact purity or concentration of the internal reference substance is not required as long as the same quantity is added to the external standard and the analyte. The new method reduces the burden of searching for an appropriate standard for each analyte significantly. Therefore the efficiency of the qNMR purity assay increases while the precision of the internal standard method is retained.

  8. Hydrocarbon type analysis of jet fuels by /sup 1/H and /sup 13/C NMR

    SciTech Connect

    Netzel, D.A.; Hunter, P.M.

    1981-05-01

    This report describes the application of NMR spectroscopy to the chemical characterization without prior chromatographic separation of jet fuels and various fuel blends containing varying amounts of paraffinic and aromatic constituents. Equations are derived by which the total percent paraffins and aromatics as well as percent monoaromatics and diaromatics can be calculated. Computer programs for the various calculations are included. The results obtained by NMR are compared to those obtained by MS.

  9. Oxidation of municipal wastewater by free radicals mechanism. A UV/Vis spectroscopy study.

    PubMed

    Giannakopoulos, E; Isari, E; Bourikas, K; Karapanagioti, H K; Psarras, G; Oron, G; Kalavrouziotis, I K

    2016-08-01

    This study investigates the oxidation of municipal wastewater (WW) by complexation with natural polyphenols having radical scavenging activity, such as (3,4,5 tri-hydroxy-benzoic acid) gallic acid (GA) in alkaline pH (>7), under ambient O2 and temperature. Physicochemical and structural characteristics of GA-WW complex-forming are evaluated by UV/Vis spectroscopy. The comparative analysis among UV/Vis spectra of GA monomer, GA-GA polymer, WW compounds, and GA-WW complex reveals significant differences within 350-450 and 500-900 nm. According to attenuated total reflectance (ATR) spectroscopy and thermogravimetric analysis (TGA), these spectra differences correspond to distinct complexes formed. This study suggests a novel role of natural polyphenols on the degradation and humification of wastes.

  10. Classification of the botanical origin for Malaysian honey using UV-Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Almaleeh, Abd Alazeez; Adom, Abdul Hamid; Fathinul-Syahir, A. S.

    2017-03-01

    The aim of this study is to perform the classification of three brands of Malaysian honeys according to their botanical origin using UV-Vis Spectroscopy. The ability to classify honey according to their botanical origin is important to ensure the quality of the product. A total of nine samples from three commercial brands of honey produces were measured by a Lambda 35 UV-Vis Spectrometer. The wavelength range recorded was from 200 nm to 400 nm and used for model calibration. The (PCs) were extracted from principal components analysis (PCA), the first three (PCs) which accounted 98.03% of disparity of the spectra were combined separately with support vector machine (SVM) for the development of (PC-SVM) model, and achieved 100% discrimination accuracy. The results can be utilized in the development of device for the classification of honey accurately and rapid as well as safe guarantee to ordinary consumers.

  11. Determination of polyphenolic compounds of red wines by UV-VIS-NIR spectroscopy and chemometrics tools.

    PubMed

    Martelo-Vidal, M J; Vázquez, M

    2014-09-01

    Spectral analysis is a quick and non-destructive method to analyse wine. In this work, trans-resveratrol, oenin, malvin, catechin, epicatechin, quercetin and syringic acid were determined in commercial red wines from DO Rías Baixas and DO Ribeira Sacra (Spain) by UV-VIS-NIR spectroscopy. Calibration models were developed using principal component regression (PCR) or partial least squares (PLS) regression. HPLC was used as reference method. The results showed that reliable PLS models were obtained to quantify all polyphenols for Rías Baixas wines. For Ribeira Sacra, feasible models were obtained to determine quercetin, epicatechin, oenin and syringic acid. PCR calibration models showed worst reliable of prediction than PLS models. For red wines from mencía grapes, feasible models were obtained for catechin and oenin, regardless the geographical origin. The results obtained demonstrate that UV-VIS-NIR spectroscopy can be used to determine individual polyphenolic compounds in red wines.

  12. Vibrationally resolved UV/Vis spectroscopy with time-dependent density functional based tight binding.

    PubMed

    Rüger, Robert; Niehaus, Thomas; van Lenthe, Erik; Heine, Thomas; Visscher, Lucas

    2016-11-14

    We report a time-dependent density functional based tight-binding (TD-DFTB) scheme for the calculation of UV/Vis spectra, explicitly taking into account the excitation of nuclear vibrations via the adiabatic Hessian Franck-Condon method with a harmonic approximation for the nuclear wavefunction. The theory of vibrationally resolved UV/Vis spectroscopy is first summarized from the viewpoint of TD-DFTB. The method is benchmarked against time-dependent density functional theory (TD-DFT) calculations for strongly dipole allowed excitations in various aromatic and polar molecules. Using the recent 3ob:freq parameter set of Elstner's group, very good agreement with TD-DFT calculations using local functionals was achieved.

  13. Time-dependent density functional theory study of UV/vis spectra of natural styrylpyrones.

    PubMed

    Anouar, El Hassane; Weber, Jean-Frédéric F

    2013-11-01

    Natural styrylpyrones isolated from fungi are known for various biological activities including antioxidant activity by scavenging free radicals. UV/vis spectra play an important role in elucidating chemical structures of these compounds via identification of chromophore units. With the aim of predicting the UV/vis spectra of a series of natural styrylpyrones, we tested TD-DFT, CIS and ZINDO methods in gas and in PCM solvent. The results showed that the individual or combined B3P86 and B3LYP hybrid functionals are suitable to predict the maximum wavelength absorption bands (λmax) for styrylpyrones. The structure property relationship (SPR) study emphasized the role of (i) structural parameters (e.g., hydrogen bond and the length of conjugated double bonds) and (ii) electronic descriptors (e.g., ionization potential, electronic affinity, hardness and electrophilicity) in bathochromic and hypsochromic shifts of maximum wavelength absorption bands (λmax) of styrylpyrone derivatives.

  14. Protonation effects on the UV/Vis absorption spectra of imatinib: a theoretical and experimental study.

    PubMed

    Grante, Ilze; Actins, Andris; Orola, Liana

    2014-08-14

    An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation.

  15. X-ray diffraction, FTIR, UV-VIS and SEM studies on chromium (III) complexes

    SciTech Connect

    Mishra, Ashutosh; Dwivedi, Jagrati Shukla, Kritika

    2015-06-24

    Five Chromium (III) complexes have been prepared using Schiff base ligands which derived from benzoin and five different amino acids (H{sub 2}N-R). Samples were characterized by XRD, FTIR, UV-VIS and SEM method. X-Ray diffraction pattern analyzed that all chromium (III) complexes have hexagonal structure and crystalline, in nature, using Bruker D8 Advance instrument. Using VERTAX 70, FTIR spectroscopy reveals that Samples have (C=N), (C-O), (M-N) and (M-O) bonds in the range of 4000-400cm{sup −1}. UV-VIS spectroscopy give information that samples absorb the visible light which is in the range of 380-780nm. For this, Lambda 960 spectrometer used. SEM is designed for studying of the solid objects, using JEOL JSM 5600 instrument.

  16. An overview of liquid phase microextraction approaches combined with UV-Vis spectrophotometry.

    PubMed

    Dehghani Mohammad Abadi, Malihe; Ashraf, Narges; Chamsaz, Mahmoud; Shemirani, Farzaneh

    2012-09-15

    Ultraviolet and visible spectrophotometer has become a popular analytical instrument in the modern day laboratories. However, the low concentrations of many analytes in samples make it difficult to directly measure them by UV-Vis spectrophotometry. This overview focuses on the combinations of microvolume UV-Vis spectrophotometry with miniaturized approaches to sample preparation, namely, single drop microextraction (SDME), dispersive liquid-liquid microextraction (DLLME), cold induced aggregation microextraction (CIAME), in situ solvent formation microextraction (ISSFME), ultrasound assisted emulsification microextraction (USAEME), solidified floating organic drop microextraction (SFODME), and hollow fiber based liquid phase microextraction (HF-LPME) to improve both the selectivity and sensitivity. Integration of these techniques provides unique advantages which include availability, simplicity of operation, low cost, speed, precision and accuracy; hence making them a powerful tool in chemical analysis.

  17. Vibrationally resolved UV/Vis spectroscopy with time-dependent density functional based tight binding

    NASA Astrophysics Data System (ADS)

    Rüger, Robert; Niehaus, Thomas; van Lenthe, Erik; Heine, Thomas; Visscher, Lucas

    2016-11-01

    We report a time-dependent density functional based tight-binding (TD-DFTB) scheme for the calculation of UV/Vis spectra, explicitly taking into account the excitation of nuclear vibrations via the adiabatic Hessian Franck-Condon method with a harmonic approximation for the nuclear wavefunction. The theory of vibrationally resolved UV/Vis spectroscopy is first summarized from the viewpoint of TD-DFTB. The method is benchmarked against time-dependent density functional theory (TD-DFT) calculations for strongly dipole allowed excitations in various aromatic and polar molecules. Using the recent 3ob:freq parameter set of Elstner's group, very good agreement with TD-DFT calculations using local functionals was achieved.

  18. Natural amber, copal resin and colophony investigated by UV-VIS, infrared and Raman spectrum

    NASA Astrophysics Data System (ADS)

    Rao, ZhiFan; Dong, Kun; Yang, XiaoYun; Lin, JinChang; Cui, XiaoYing; Zhou, RongFeng; Deng, Qing

    2013-08-01

    Natural amber, copal resin and colophony are have investigated by UV-VIS, infrared and Raman spectrum. In order to distinguish the natural amber, copal resin and colophony, we have successfully used the nondestructive examination (NDE) technology. The results show that UV-VIS could not distinguish these compositions. The infrared spectra can distinguish them, but the technology may destroy the specimen. The Raman spectra show three characteristic peaks of vibration near position 932 cm-1 and position 1179 cm-1 of copal resin, which confirm the existence of terpenes compounds in it. In the Raman spectra of colophony, the vibration characteristic peak at position 1589 cm-1, caused by the conjugate double bond of internal unsaturated resin acid, is the basis of the characteristic difference between colophony and natural amber. The advantages of the distinguished technology by Raman spectroscopy are convenient and nondestructive examination for natural amber, copal resin and colophony.

  19. UV-VIS spectroscopic study of one pot synthesized strontium oxide quantum dots

    NASA Astrophysics Data System (ADS)

    Nemade, K. R.; Waghuley, S. A.

    The properties of drastically change when matter makes transition from 1D, 2D, 3D, to 0D. The quantum dots (QDs) of strontium oxide (SrO) were synthesized by one pot chemical precipitation method using hexamethylenetetramine (HMT). The radius of SrO QDs was calculated from hyperbolic band model (HBM). The direct and indirect band gaps of SrO QDs were estimated from UV-VIS analysis. The particle size was found to be 2.48 nm. The quantum confinement effect in SrO QDs is discussed through exciton Bohr radius. The particle size from UV-VIS analysis is in excellent agreement with fluorescence and TEM.

  20. Light induced E-Z isomerization in a multi-responsive organogel: elucidation from (1)H NMR spectroscopy.

    PubMed

    Mondal, Sanjoy; Chakraborty, Priyadarshi; Bairi, Partha; Chatterjee, Dhruba P; Nandi, Arun K

    2015-07-07

    A multiresponsive organogel of (E)-N'-(anthracene-10-ylmethylene)-3,4,5-tris(dodecyloxy)benzohydrazide (I) showed a decrease of fluorescence intensity, decrease in mechanical strength and a change in gel morphology on irradiation with a wavelength of 365 nm. This is attributed to the E-Z isomerization across the C=N bond of I as evidenced from (1)H NMR spectroscopy.

  1. Method of Continuous Variation: Characterization of Alkali Metal Enolates Using 1H and 19F NMR Spectroscopies

    PubMed Central

    2015-01-01

    The method of continuous variation in conjunction with 1H and 19F NMR spectroscopies was used to characterize lithium and sodium enolates solvated by N,N,N′,N′-tetramethylethyldiamine (TMEDA) and tetrahydrofuran (THF). A strategy developed using lithium enolates was then applied to the more challenging sodium enolates. A number of sodium enolates solvated by TMEDA or THF afford exclusively tetramers. Evidence suggests that TMEDA chelates sodium on cubic tetramers. PMID:24915602

  2. On the role of experimental imperfections in constructing (1)H spin diffusion NMR plots for domain size measurements.

    PubMed

    Nieuwendaal, Ryan C

    2016-01-01

    We discuss the precision of 1D chemical-shift-based (1)H spin diffusion NMR experiments as well as straightforward experimental protocols for reducing errors. The (1)H spin diffusion NMR experiments described herein are useful for samples that contain components with significant spectral overlap in the (1)H NMR spectrum and also for samples of small mass (<1mg). We show that even in samples that display little spectral contrast, domain sizes can be determined to a relatively high degree of certainty if common experimental variability is accounted for and known. In particular, one should (1) measure flip angles to high precision (≈±1° flip angle), (2) establish a metric for phase transients to ensure their repeatability, (3) establish a reliable spectral deconvolution procedure to ascertain the deconvolved spectra of the neat components in the composite or blend spin diffusion spectrum, and (4) when possible, perform 1D chemical-shift-based (1)H spin diffusion experiments with zero total integral to partially correct for errors and uncertainties if these requirements cannot fully be implemented. We show that minimizing the degree of phase transients is not a requirement for reliable domain size measurement, but their repeatability is essential, as is knowing their contribution to the spectral offset (i.e. the J1 coefficient). When performing experiments with zero total integral in the spin diffusion NMR spectrum with carefully measured flip angles and known phase transient effects, the largest contribution to error arises from an uncertainty in the component lineshapes which can be as high as 7%. This uncertainty can be reduced considerably if the component lineshapes deconvolved from the composite or blend spin diffusion spectra adequately match previously acquired pure component spectra.

  3. Identification of isomeric dicaffeoylquinic acids from Eleutherococcus senticosus using HPLC-ESI/TOF/MS and 1H-NMR methods.

    PubMed

    Tolonen, Ari; Joutsamo, Topi; Mattlla, Sampo; Kämäräinen, Terttu; Jalonen, Jorma

    2002-01-01

    Liquid chromatography-electrospray time-of-flight mass spectrometry (HPLC-ESI/TOF/MS) and a novel NMR technique, developed to maximise the sensitivity obtained from the standard NMR spectrometer, have been applied to the identification of the phenolic constituents of Eleutherococcus senticosus. In addition, molecular modelling and dihedral bond angle calculations based on the vicinal 3JHH-coupling constants have been used in the unambiguous assignment of signals in the 1H-NMR spectra. 5'-O-Caffeoylquinic acid and three isomeric compounds, 1',5'-O-dicaffeoylquinic acid, 3',5'-O-dicaffeoylquinic acid and 4',5'-O-dicaffeoylquinic acid, have been isolated and identified from a sample. The isolation and structure determination of the latter two compounds are reported for the first time from this plant.

  4. Qualitative and quantitative analyses of Compound Danshen extract based on (1)H NMR method and its application for quality control.

    PubMed

    Yan, Kai-Jing; Chu, Yang; Huang, Jian-Hua; Jiang, Miao-Miao; Li, Wei; Wang, Yue-Fei; Huang, Hui-Yong; Qin, Yu-Hui; Ma, Xiao-Hui; Zhou, Shui-Ping; Sun, Henry; Wang, Wei

    2016-11-30

    In this study, a new approach using (1)H NMR spectroscopy combined with chemometrics method was developed for qualitative and quantitative analyses of extracts of Compound Danshen Dripping Pills (CDDP). For the qualitative analysis, some metabolites presented in Compound Danshen extract (CDE, extraction intermediate of CDDP) were detected, including phenolic acids, saponins, saccharides, organic acids and amino acids, by the proposed (1)H NMR method, and metabolites profiles were further analyzed by selected chemometrics algorithms to define the threshold values for product quality evaluation. Moreover, three main phenolic acids (danshensu, salvianolic acid B, and procatechuic aldehyde) in CDE were determined simultaneously, and method validation in terms of linearity, precision, repeatability, accuracy, and stability of the dissolved target compounds in solution was performed. The average recoveries varied between 84.20% and 110.75% while the RSDs were below 6.34% for the three phenolic acids. This (1)H NMR method offers an integral view of the extract composition, allows the qualitative and quantitative analysis of CDDP, and has the potential to be a supplementary tool to UPLC/HPLC for quality assessment of Chinese herbal medicines.

  5. Molecular characterization of dissolved organic matter in glacial ice: coupling natural abundance 1H NMR and fluorescence spectroscopy.

    PubMed

    Pautler, Brent G; Woods, Gwen C; Dubnick, Ashley; Simpson, André J; Sharp, Martin J; Fitzsimons, Sean J; Simpson, Myrna J

    2012-04-03

    Glaciers and ice sheets are the second largest freshwater reservoir in the global hydrologic cycle, and the onset of global climate warming has necessitated an assessment of their contributions to sea-level rise and the potential release of nutrients to nearby aquatic environments. In particular, the release of dissolved organic matter (DOM) from glacier melt could stimulate microbial activity in both glacial ecosystems and adjacent watersheds, but this would largely depend on the composition of the material released. Using fluorescence and (1)H NMR spectroscopy, we characterize DOM at its natural abundance in unaltered samples from a number of glaciers that differ in geographic location, thermal regime, and sample depth. Parallel factor analysis (PARAFAC) modeling of DOM fluorophores identifies components in the ice that are predominantly proteinaceous in character, while (1)H NMR spectroscopy reveals a mixture of small molecules that likely originate from native microbes. Spectrofluorescence also reveals a terrestrial contribution that was below the detection limits of NMR; however, (1)H nuclei from levoglucosan was identified in Arctic glacier ice samples. This study suggests that the bulk of the DOM from these glaciers is a mixture of biologically labile molecules derived from microbes.

  6. Mechanisms of humic acids degradation by white rot fungi explored using 1H NMR spectroscopy and FTICR mass spectrometry.

    PubMed

    Grinhut, Tzafrir; Hertkorn, Norbert; Schmitt-Kopplin, Philippe; Hadar, Yitzhak; Chen, Yona

    2011-04-01

    Enzymatic activities involved in decay processes of natural aromatic macromolecules, such as humic acids (HA) and lignin by white rot fungi, have been widely investigated. However, the physical and chemical analysis of degradation products of these materials has not been intensively explored. Fourier transform cyclotron resonance mass spectrometry (FTICR MS) and 1H NMR as well as CHNOS and size exclusion chromatography were employed to study the mechanisms of HA degradation by Trametes sp. M23 and Phanerochaete sp. Y6. Size exclusion chromatography analyses demonstrate and provide evidence for HA breakdown into low MW compounds. The 1H NMR analysis revealed oxidation, a decrease in the aromatic content, and an indication of demethylation of the HA during biodegradation. Evidence for oxidation was also obtained using CHNOS. Analysis of FTICR MS results using a new software program developed by our group (David Mass Sort) revealed consecutive series of masses suggesting biochemical degradation trends such as oxidation, aromatic cleavage, and demethylation. These results are in agreement with the 1H NMR analysis and with the suggested role of the ligninolytic system leading to HA degradation.

  7. Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination of isomers of 1,4-diketone derivatives.

    PubMed

    Xu, Guohua; Yin, Guodong; Guo, Wenbo; Wu, Anxin; Cui, Yanfang

    2008-01-01

    Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination for a series of new isomers of 1,4-diketone derivatives obtained via self-sorting tandem reaction were accomplished by means of one- and two-dimentional NMR experiments including 1H, 13C, gCOSY, gHSQC, gHMBC, and NOESY.

  8. Metabolic Characterization of Advanced Liver Fibrosis in HCV Patients as Studied by Serum 1H-NMR Spectroscopy.

    PubMed

    Embade, Nieves; Mariño, Zoe; Diercks, Tammo; Cano, Ainara; Lens, Sabela; Cabrera, Diana; Navasa, Miquel; Falcón-Pérez, Juan M; Caballería, Joan; Castro, Azucena; Bosch, Jaume; Mato, José M; Millet, Oscar

    2016-01-01

    Several etiologies result in chronic liver diseases including chronic hepatitis C virus infection (HCV). Despite its high incidence and the severe economic and medical consequences, liver disease is still commonly overlooked due to the lack of efficient non-invasive diagnostic methods. While several techniques have been tested for the detection of fibrosis, the available biomarkers still present severe limitations that preclude their use in clinical diagnostics. Liver diseases have also been the subject of metabolomic analysis. Here, we demonstrate the suitability of 1H NMR spectroscopy for characterizing the metabolism of liver fibrosis induced by HCV. Serum samples from HCV patients without fibrosis or with liver cirrhosis were analyzed by NMR spectroscopy and the results were submitted to multivariate and univariate statistical analysis. PLS-DA test was able to discriminate between advanced fibrotic and non-fibrotic patients and several metabolites were found to be up or downregulated in patients with cirrhosis. The suitability of the most significantly regulated metabolites was validated by ROC analysis. Our study reveals that choline, acetoacetate and low-density lipoproteins are the most informative biomarkers for predicting cirrhosis in HCV patients. Our results demonstrate that statistical analysis of 1H-NMR spectra is able to distinguish between fibrotic and non-fibrotic patients suffering from HCV, representing a novel diagnostic application for NMR spectroscopy.

  9. Quantification of omeprazole degradation by enteric coating polymers: an UV-VIS spectroscopy study.

    PubMed

    Riedel, A; Leopold, C S

    2005-02-01

    The aim of this study was to investigate the degradation of the acid-labile proton-pump-inhibitor omeprazole in organic polymer solutions and aqueous dispersions of enteric coating polymers by UV spectroscopy. Furthermore, data were compared with those obtained in a previous HPLC study. For comparative purposes the cationic Eudragit RS 100 and the monomeric acid acetic acid were included in this study. The discolorations of degraded omeprazole solutions were analysed by VIS spectroscopy. UV-VIS spectra were recorded after preparation of the solutions and after 180 min of storage. The change of absorption was calculated as the difference of the absorption values at 305 nm. Degradation of omeprazole depends on the amount of acidic groups in the polymer structure. This decomposition manifests itself in a shifting of the absorption maximum to lower wavelengths and a decrease of absorption intensity. UV-VIS spectroscopy was used to determine the extent of degradation induced by enteric polymers. A good correlation of these results with previous HPLC data was found when excluding UV absorbing polymers. Nevertheless, values obtained by UV-VIS spectroscopy were always lower than those obtained by HPLC. For evaluation of the discoloration of degraded omeprazole solutions, VIS spectroscopy is a simple and fast method.

  10. UV-Vis Ratiometric Resonance Synchronous Spectroscopy for Determination of Nanoparticle and Molecular Optical Cross Sections.

    PubMed

    Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

    2016-03-01

    Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.

  11. Artificial neural network associated to UV/Vis spectroscopy for monitoring bioreactions in biopharmaceutical processes.

    PubMed

    Takahashi, Maria Beatriz; Leme, Jaci; Caricati, Celso Pereira; Tonso, Aldo; Fernández Núñez, Eutimio Gustavo; Rocha, José Celso

    2015-06-01

    Currently, mammalian cells are the most utilized hosts for biopharmaceutical production. The culture media for these cell lines include commonly in their composition a pH indicator. Spectroscopic techniques are used for biopharmaceutical process monitoring, among them, UV-Vis spectroscopy has found scarce applications. This work aimed to define artificial neural networks architecture and fit its parameters to predict some nutrients and metabolites, as well as viable cell concentration based on UV-Vis spectral data of mammalian cell bioprocess using phenol red in culture medium. The BHK-21 cell line was used as a mammalian cell model. Off-line spectra of supernatant samples taken from batches performed at different dissolved oxygen concentrations in two bioreactor configurations and with two pH control strategies were used to define two artificial neural networks. According to absolute errors, glutamine (0.13 ± 0.14 mM), glutamate (0.02 ± 0.02 mM), glucose (1.11 ± 1.70 mM), lactate (0.84 ± 0.68 mM) and viable cell concentrations (1.89 10(5) ± 1.90 10(5) cell/mL) were suitably predicted. The prediction error averages for monitored variables were lower than those previously reported using different spectroscopic techniques in combination with partial least squares or artificial neural network. The present work allows for UV-VIS sensor development, and decreases cost related to nutrients and metabolite quantifications.

  12. Examples of UV-Vis profiles use as tool for evidence of the metallophthalocyanines transformation

    NASA Astrophysics Data System (ADS)

    Kubiak, Ryszard; Dyrda, Gabriela; Ejsmont, Krzysztof

    2017-02-01

    The UV-Vis spectra for a set of MPcs (Mmetal, Pc = phthalocyanine ligand), i.e.: In(III)PcI (1), Hf(IV)PcI2Pht (Pht = phthalonitrile) (2), Sn(II)Pc (3), Sn(IV)PcI2(4), and Ge(IV)PcI2(5) have been examined in two solvents, O-donative acetylacetone, and non-coordinative benzene. The UV-Vis spectra in Hacac solution of 1,2 and 4,5 shows that the axially ligated iodine atoms are replaced by (acac)- anions of the solvent, whereas in 3 the oxygen donors of the solvent causing the auto-oxidation of Sn(II) to Sn(IV) ions and as a result the Sn(II)Pc is transformed into the Sn(IV)Pc(acac)2. The chloride complexes of the 1-5 compounds are formed at Hacac solution after acidification by hydrochloric acid, however each compound solution behaviors specifically. The UV-Vis spectra collected for the studied compounds at benzene solvent both before and after the solution acidization clearly indicate that the respective Q band character (besides 3) remains practically unchanged. The presence of the Cl- ions at the Sn(II)Pc solution in benzene results in the formation of Sn(IV)PcCl2.

  13. Optical absorption of sodium copper chlorophyllin thin films in UV-vis-NIR region.

    PubMed

    Farag, A A M

    2006-11-01

    The optical absorption studies of sodium copper chlorophyllin thin films (SCC), prepared by spray pyrolysis, in the UV-vis-NIR region was reported for the first time. Several new discrete transitions are observed in the UV-vis region of the spectra in addition to a strong continuum component in the IR region. The spectra of the infrared absorption allow characterization of vibration modes for the powder and thin films of SCC. The absorption spectrum recorded in the UV-vis region showed different absorption bands, namely the Soret (B) in the region 340-450 nm and Q-band in the region 600-700 nm and other band labeled N in the 240-320 region. Some important spectral parameters namely optical absorption coefficient (alpha), molar extinction coefficient (epsilon(molar)), oscillator strength (f), electric dipole strength (q(2)) and absorption half bandwidth (Deltalambda) of the principle optical transitions were evaluated. The analysis of the absorption coefficient in the absorption region revealed direct transitions and the energy gap was estimated as 1.63 eV. Discussion of the obtained results and their comparison with the previous published data are also given.

  14. Radical protection by differently composed creams in the UV/VIS and IR spectral ranges.

    PubMed

    Meinke, Martina C; Syring, Felicia; Schanzer, Sabine; Haag, Stefan F; Graf, Rüdiger; Loch, Manuela; Gersonde, Ingo; Groth, Norbert; Pflücker, Frank; Lademann, Jürgen

    2013-01-01

    Modern sunscreens are well suited to provide sufficient protection in the UV range because the filter substances absorb or scatter UV radiation. Although up to 50% of radicals are formed in the visible and infrared spectral range during solar radiation protection strategies are not provided in this range. Previous investigations of commercially available products have shown that in addition to physical filters, antioxidants (AO) are necessary to provide protective effects in the infrared range by neutralizing already formed radicals. In this study, the efficacy of filter substances and AO to reduce radical formation in both spectral ranges was investigated after UV/VIS or IR irradiation. Optical properties and radical protection were determined for the investigated creams. It was found that organic UV filters lower radical formation in the UV/VIS range to 35% compared to untreated skin, independent of the presence of AO. Further reduction to 14% was reached by addition of 2% physical filters, whereas physical filters alone were ineffective in the UV/VIS range due to the low concentration. In contrast, this filter type reduced radical formation in the IR range significantly to 65%; similar effects were aroused after application of AO. Sunscreens which contain organic UV filters, physical filters and AO ensure protection in the complete solar spectrum.

  15. Application of quantitative 1H NMR for the calibration of protoberberine alkaloid reference standards.

    PubMed

    Wu, Yan; He, Yi; He, Wenyi; Zhang, Yumei; Lu, Jing; Dai, Zhong; Ma, Shuangcheng; Lin, Ruichao

    2014-03-01

    Quantitative nuclear magnetic resonance spectroscopy (qNMR) has been developed into an important tool in the drug analysis, biomacromolecule detection, and metabolism study. Compared with mass balance method, qNMR method bears some advantages in the calibration of reference standard (RS): it determines the absolute amount of a sample; other chemical compound and its certified reference material (CRM) can be used as internal standard (IS) to obtain the purity of the sample. Protoberberine alkaloids have many biological activities and have been used as reference standards for the control of many herbal drugs. In present study, the qNMR methods were developed for the calibration of berberine hydrochloride, palmatine hydrochloride, tetrahydropalmatine, and phellodendrine hydrochloride with potassium hydrogen phthalate as IS. Method validation was carried out according to the guidelines for the method validation of Chinese Pharmacopoeia. The results of qNMR were compared with those of mass balance method and the differences between the results of two methods were acceptable based on the analysis of estimated measurement uncertainties. Therefore, qNMR is an effective and reliable analysis method for the calibration of RS and can be used as a good complementarity to the mass balance method.

  16. Synthesis of enantiopure oxorhenium(V) and arylimidorhenium(V) "3 + 2" Schiff base complexes. X-ray diffraction, cyclic voltammetry, UV-vis, and circular dichroism characterizations.

    PubMed

    Béreau, V M; Khan, S I; Abu-Omar, M M

    2001-12-17

    Two new oxorhenium(V) and two new arylimidorhenium(V) complexes of the Schiff base ligands 2-hydroxybenzaldehyde-((1R,2S)-1-amino-2-indanol)imine (1) (H(2)L(1)) and 3-(1-adamantyl)-2-hydroxy-5-methylbenzaldehyde-((1R,2S)-1-amino- 2-indanol)imine (2) (H(2)L(2)) have been prepared from the reaction of the precursor Re(O)(PPh(3))(2)Cl(3), Re(NC(6)H(5))(PPh(3))(2)Cl(3), or Re(NC(6)H(4)OCH(3))(PPh(3))(2)Cl(3) and the free ligands H(2)L(1,2). The complexes Re(O)(HL(1))(L(1)) (3), Re(O)(HL(2))(L(2)) (4), Re(NC(6)H(5))(HL(1))(L(1)) (5), and Re(NC(6)H(4)OCH(3))(HL(1))(L(1)) (6) have been isolated and fully characterized by IR, (1)H NMR, circular dichroism, LRMS-FAB, and elemental analysis. All the complexes have a chiral center at rhenium. A single enantiomer is obtained in all cases. Suitable crystals of 3 and 5 were used in X-ray structural determinations. Crystal data: (3) C(32)H(27)N(2)O(5)Re.CH(2)Cl(2), orthorhombic, P2(1)2(1)2(1), a = 9.5599(16) A, b = 9.9579(16) A, c = 31.712(5) A, V = 3018.9(9) A(3), T = 100(2) K, Z = 4. (5) C(40)H(38)N(3)O(5)Re, monoclinic, P2(1), a = 9.286(3) A, b = 18.759(6) A, c = 9.957(3) A, beta = 102.817(6) degrees, V = 1691.3(10) A(3), T = 100(2) K, Z = 2. The major characteristic of these complexes is the presence of two coordination modes for the Schiff base ligands on rhenium, a tridentate ligand (noted L(1,2)) and another bidentate ligand (noted HL(1,2)). In the latter, the -OH group of the indanol is free and tilts away from the coordination sphere. X-ray structural analyses in conjunction with circular dichroism were used to assign the absolute configuration at rhenium (C). Cyclic voltammetry, UV-vis, and circular dichroism data are presented and discussed. The complexes were found to be highly stable and to resist reduction even when treated with organic phosphanes.

  17. Probing hydrogen bonding in cocrystals and amorphous dispersions using (14)N-(1)H HMQC solid-state NMR.

    PubMed

    Tatton, Andrew S; Pham, Tran N; Vogt, Frederick G; Iuga, Dinu; Edwards, Andrew J; Brown, Steven P

    2013-03-04

    Cocrystals and amorphous solid dispersions have generated interest in the pharmaceutical industry as an alternative to more established solid delivery forms. The identification of intermolecular hydrogen bonding interactions in a nicotinamide palmitic acid cocrystal and a 50% w/w acetaminophen-polyvinylpyrrolidone solid dispersion are reported using advanced solid-state magic-angle spinning (MAS) NMR methods. The application of a novel (14)N-(1)H HMQC experiment, where coherence transfer is achieved via through-space couplings, is shown to identify specific hydrogen bonding motifs. Additionally, (1)H isotropic chemical shifts and (14)N electric field gradient (EFG) parameters, both accessible from (14)N-(1)H HMQC experiments, are shown to be sensitive to changes in hydrogen bonding geometry. Numerous indicators of molecular association are accessible from this experiment, including NH cross-peaks occurring from intermolecular hydrogen bonds and changes in proton chemical shifts or electric field gradient parameters. First-principles calculations using the GIPAW approach that yield accurate estimates of isotropic chemical shifts, and EFG parameters were used to assist in assignment. It is envisaged that (14)N-(1)H HMQC solid state NMR experiments could become a valuable screening technique of solid delivery forms in the pharmaceutical industry.

  18. Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR.

    PubMed

    Somashekar, B S; Nagana Gowda, G A; Ramesha, A R; Khetrapal, C L

    2004-07-01

    A protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl-[2-(1-phenyl-1-pyridin-2-yl-ethoxy)ethyl]amine, in solution using one- and two-dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in 'intermediate' exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about -30 degrees C. A two-dimensional 1H-1H double quantum filtered correlation experiment carried out at -55 degrees C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two-dimensional rotating frame 1H-1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings.

  19. Nondestructive Quantification of Local Plasticizer Concentration in PVC by (1)H NMR Relaxometry.

    PubMed

    Adams, Alina; Kwamen, Rance; Woldt, Benjamin; Graß, Michael

    2015-12-01

    The properties of plasticized poly(vinyl chloride) (PVC) , one of the most important polymers today, are strongly dictated by the concentration of plasticizer. Yet, it has been impossible to quantify this concentration at different positions inside a PVC product without its destruction because of a lack of suitable analytical methods. Thus, this paper introduces a simple, fast, and efficient way to determine truly nondestructively the concentration of plasticizer in PVC by single-sided nuclear magnetic resonance (NMR). With the help of correlation curves between the concentration of plasticizer inside nonaged PVC samples and the corresponding volume-averaged NMR parameters, single-sided NMR allows the quantification of the local concentration of plasticizer in aged PVC plates at different depths by spatially resolved relaxation measurements. The presented approach represents a fundamental step toward in situ characterization of plasticized PVC.

  20. New NO donor ligands and complexes containing furfuryl or crown ether moiety: Syntheses, crystal structures and tautomerism in ortho-hydroxy substituted compounds as studied by UV-vis spectrophotometry

    NASA Astrophysics Data System (ADS)

    Şahin, Duygu; Koçoğlu, Serhat; Şener, Öznur; Şenol, Cemal; Dal, Hakan; Hökelek, Tuncer; Hayvalı, Zeliha

    2015-12-01

    NO donor ligands were prepared by the condensation of methoxy substituted salicylaldehyde with 5-methylfurfurylamine (1 and 2) and 4‧-aminobenzo-15-crown 5 (3-5). New crown ether ligands of Schiff base type (3-5) containing recognition sites for alkali metal and transition guest cations. Ni(II) complexes (1a-5a) have been synthesized with bidentate NO donor Schiff base ligands (1-5) with Ni(CH3COO)2.·4H2O. Monotopic crystalline 1:1 (Na+:ligand) sodium complexes (3b-5b) of the crown ether ligands were also prepared. Schiff bases (1-5) and complexes (1a-5a, 3b-5b) were characterized by elemental analyses, FT-IR, 1H-, 13C-NMR and mass spectroscopies. The crystal structures of 1, 1a and 2 were verified by X-ray diffraction analysis. The tautomeric equilibria (phenol-imine, O-H⋯N and keto-amine, O⋯H-N forms) have been systematically studied by using UV-vis spectrophotometry for the o-hydroxy substituted compounds (1-5). The UV-visible spectra of these ligands (1-5) were recorded and commented in polar, non-polar, acidic and basic media.

  1. [Using UV-Vis Absorbance for Characterization of Maturity in Composting Process with Different Materials].

    PubMed

    Zhao, Yue; Wei, Yu-quan; Li, Yang; Xi, Bei-dou; Wei, Zi-min; Wang, Xing-lei; Zhao, Zhi-nan; Ding, Jei

    2015-04-01

    The present study was conducted to assess the degree of humification in DOM during composting using different raw materials, and their effect on maturity of compost based on UV-Vis spectra measurements and chemometrics method. The raw materials of composting studied included chicken manure, pig manure, kitchen waste, lawn waste, fruits and vegetables waste, straw waste, green waste, sludge, and municipal solid waste. During composting, the parameters of UV-Vis spectra of DOM, including SUVA254 , SUVA280 , E250/E365, E4/E6, E2/E4, E2/E6, E253/E203, E253/E220, A226-400, S275-295 and S350-400 were calculated, Statistical analysis indicated that all the parameter were significantly changed during composting. SUVA254 and SUVA280 of DOM were continuously increased, E250/E365 and E4/E6 were continuously decreased in DOM, while A226-400, S275-295 and S350-400 of DOM at the final stage were significantly different with those at other stages of composting. Correlation analysis indicated that the parameters were significantly correlated with each other except for E2/E4 and E235/E203. Furthermore, principal component analysis suggested that A226-400, SUVA254, S350-400, SUVA280 and S275~295 were reasonable parameters for assessing the compost maturity. To distinguish maturity degree among different composts, hierarchical cluster analysis, an integrated tool utilizing multiple UV-Vis parameters, was performed based on the data (A226-400, SUVA254, S350-400, SUVA280 and S275-295) of DOM derived from the final stage of composting. Composts from different sources were clustered into 2 groups. The first group included chicken manure, pig manure, lawn waste, fruits and vegetables waste, green waste, sludge, and municipal solid waste characterized by a lower maturity degree, and the second group contained straw waste and kitchen waste associated with a higher maturity degree. The above results suggest that a multi-index of UV-Vis spectra could accurately evaluate the compost maturity

  2. Glycerin-Induced Conformational Changes in Bombyx mori Silk Fibroin Film Monitored by 13C CP/MAS NMR and 1H DQMAS NMR

    PubMed Central

    Asakura, Tetsuo; Endo, Masanori; Hirayama, Misaki; Arai, Hiroki; Aoki, Akihiro; Tasei, Yugo

    2016-01-01

    In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, 13C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared. Upon further increase in Glyc concentration, the percentage of Silk I* increased linearly up to 9 wt % Glyc and then tended to be almost constant (30%). This value (30%) was the same as the fraction of Ala residue within the Silk I* form out of all Ala residues of SF present in B. mori mature silkworm. The 1H DQMAS NMR spectra of Glyc-blended SF films confirmed the appearance of Silk I* in the Glyc-blended SF film. A structural model of Glyc-SF complex including the Silk I* form was proposed with the guidance of the Molecular Dynamics (MD) simulation using 1H–1H distance constraints obtained from the 1H Double-Quantum Magic Angle Spinning (DQMAS) NMR spectra. PMID:27618034

  3. Gelified Biofluids for High-Resolution Magic Angle Spinning (1)H NMR Analysis: The Case of Urine.

    PubMed

    Takis, Panteleimon G; Tenori, Leonardo; Ravera, Enrico; Luchinat, Claudio

    2017-01-17

    In this letter, we propose an alternative, effective protocol for metabolomic characterization of biofluids based on their gelification and subsequent application of high-resolution magic angle spinning (HRMAS) (1)H nuclear magnetic resonance (NMR). The sample handling is very rapid and reproducible, and much less than 40 μL of neat urine are needed to obtain a sample. Our results indicate that the HRMAS spectra of gelified urine encompass all metabolites in the NMR fingerprint, as observed by solution NMR. The proposed approach can be efficiently integrated into the NMR based metabolomics analyses routines: multivariate statistical analysis of both solution and HRMAS data produced very similar statistical models, with high classification accuracy. One of the key advantages offered by the gelification approach is the improved short-term (up to 24 h) preservation of nonfrozen HRMAS NMR gel urine samples compared to the solution samples, which could lead to an alternative way for transportation or domestic collection of biofluids, without the need of cold-storage and reducing the risks of leakage.

  4. 1H NMR studies distinguish the water soluble metabolomic profiles of untransformed and RAS-transformed cells

    PubMed Central

    Marks, Vered; Munoz, Anisleidys; Rai, Priyamvada

    2016-01-01

    Metabolomic profiling is an increasingly important method for identifying potential biomarkers in cancer cells with a view towards improved diagnosis and treatment. Nuclear magnetic resonance (NMR) provides a potentially noninvasive means to accurately characterize differences in the metabolomic profiles of cells. In this work, we use 1H NMR to measure the metabolomic profiles of water soluble metabolites extracted from isogenic control and oncogenic HRAS-, KRAS-, and NRAS-transduced BEAS2B lung epithelial cells to determine the robustness of NMR metabolomic profiling in detecting differences between the transformed cells and their untransformed counterparts as well as differences among the RAS-transformed cells. Unique metabolomic signatures between control and RAS-transformed cell lines as well as among the three RAS isoform-transformed lines were found by applying principal component analysis to the NMR data. This study provides a proof of principle demonstration that NMR-based metabolomic profiling can robustly distinguish untransformed and RAS-transformed cells as well as cells transformed with different RAS oncogenic isoforms. Thus, our data may potentially provide new diagnostic signatures for RAS-transformed cells. PMID:27330862

  5. High-Frequency (1)H NMR Chemical Shifts of Sn(II) and Pb(II) Hydrides Induced by Relativistic Effects: Quest for Pb(II) Hydrides.

    PubMed

    Vícha, Jan; Marek, Radek; Straka, Michal

    2016-10-17

    The role of relativistic effects on (1)H NMR chemical shifts of Sn(II) and Pb(II) hydrides is investigated by using fully relativistic DFT calculations. The stability of possible Pb(II) hydride isomers is studied together with their (1)H NMR chemical shifts, which are predicted in the high-frequency region, up to 90 ppm. These (1)H signals are dictated by sizable relativistic contributions due to spin-orbit coupling at the heavy atom and can be as large as 80 ppm for a hydrogen atom bound to Pb(II). Such high-frequency (1)H NMR chemical shifts of Pb(II) hydride resonances cannot be detected in the (1)H NMR spectra with standard experimental setup. Extended (1)H NMR spectral ranges are thus suggested for studies of Pb(II) compounds. Modulation of spin-orbit relativistic contribution to (1)H NMR chemical shift is found to be important also in the experimentally known Sn(II) hydrides. Because the (1)H NMR chemical shifts were found to be rather sensitive to the changes in the coordination sphere of the central metal in both Sn(II) and Pb(II) hydrides, their application for structural investigation is suggested.

  6. (1)H and (13)C NMR chemical shifts of methacrylate molecules associated with DMPC and/or DPPC liposomes.

    PubMed

    Fujisawa, Seiichiro; Ishihara, Mariko; Kadoma, Yoshinori

    2005-01-01

    In the light of recent developments, changes in (1)H and (13)C NMR chemical shifts of methacrylate molecule associated with DMPC (L-alpha dimyristoylphosphatidylcholine) or DPPC (L-alpha-dipalmitoylphosphatidylcholine) liposomes as a model for mimic native lipid bilayers were studied at 30, 37, and 52 degrees C. The chemical shifts of 3Ha, 3C, and 4C resonances in methacrylates (see Fig. 2) were greatly shifted higher field, suggesting the methacrylate molecule-lipid bilayer interaction. Comparison of the findings with methyl methacrylate (MMA), ethylene dimethacrylate (EDMA), and triethyleneglycol dimethacrylate (TEGDMA) revealed that the interaction of dimethacrylates (EDMA, TEGDMA) was greater than monomethacrylate, MMA. Their interaction with DMPC liposomes was also judged by a differential scanning calorimetry (DSC), indicating that the interaction was characterized by decreasing the enthalpy, entropy, and transition co-operativity. The evidence of the upfield NMR-shifts for methacrylate molecules was also judged by the descriptors such as the reactivity (HOMO-LUMO energy) and the electrostatic function (partial charges) between methacrylate molecules and DPPC, calculated by a PM 3 semiempirical MO method. The upfield NMR shifts were considerably well interpreted from the descriptors. NMR screening technique in methacrylates to phospholipid targets would be highly valuable in biomaterial developments. Figure 2 Changes in (1)H and (13)C NMR chemical shifts of methacrylate molecule associated with DMPC or DPPC liposomes. DMPC liposomes/MMA (1:1, molar ratio) and DMPC/TEGDMA (1:1) liposomes were measured at 30 degrees C. In DPPC liposome system, the rippled gel phase was measured at 30 degrees C, whereas the liquid crystalline phase for MMA and for both EDMA and TEGDMA were measured at 52 degrees C and 37 degrees C, respectively.

  7. In vivo1H NMR spectroscopy of the human brain at 9.4 T: Initial results

    NASA Astrophysics Data System (ADS)

    Deelchand, Dinesh Kumar; Moortele, Pierre-François Van de; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Thomas Vaughan, J.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-09-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 T. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 T. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (<100 ms) at 9.4 T. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/T from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 T. At very high field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth.

  8. Analysis of amorphous solid dispersions using 2D solid-state NMR and (1)H T(1) relaxation measurements.

    PubMed

    Pham, Tran N; Watson, Simon A; Edwards, Andrew J; Chavda, Manisha; Clawson, Jacalyn S; Strohmeier, Mark; Vogt, Frederick G

    2010-10-04

    Solid-state NMR (SSNMR) can provide detailed structural information about amorphous solid dispersions of pharmaceutical small molecules. In this study, the ability of SSNMR experiments based on dipolar correlation, spin diffusion, and relaxation measurements to characterize the structure of solid dispersions is explored. Observation of spin diffusion effects using the 2D (1)H-(13)C cross-polarization heteronuclear correlation (CP-HETCOR) experiment is shown to be a useful probe of association between the amorphous drug and polymer that is capable of directly proving glass solution formation. Dispersions of acetaminophen and indomethacin in different polymers are examined using this approach, as well as (1)H double-quantum correlation experiments to probe additional structural features. (1)H-(19)F CP-HETCOR serves a similar role for fluorinated drug molecules such as diflunisal in dispersions, providing a rapid means to prove the formation of a glass solution. Phase separation is detected using (13)C, (19)F, and (23)Na-detected (1)H T(1) experiments in crystalline and amorphous solid dispersions that contain small domains. (1)H T(1) measurements of amorphous nanosuspensions of trehalose and dextran illustrate the ability of SSNMR to detect domain size effects in dispersions that are not glass solutions via spin diffusion effects. Two previously unreported amorphous solid dispersions involving up to three components and containing voriconazole and telithromycin are analyzed using these experiments to demonstrate the general applicability of the approach.

  9. Comprehensive non-targeted analysis of contaminated groundwater of a former ammunition destruction site using 1H-NMR and HPLC-SPE-NMR/TOF-MS.

    PubMed

    Godejohann, Markus; Heintz, Lea; Daolio, Cristina; Berset, Jean-Daniel; Muff, Daniel

    2009-09-15

    The aim of the present study was to explore the capabilities of the combination of 1H NMR (proton nuclear magnetic resonance) mixture analysis and HPLC-SPE-NMR/TOF-MS (high-performance liquid chromatography coupled to solid-phase extraction and nuclear magnetic resonance and time-of-flight mass spectrometry) for the characterization of xenobiotic contaminants in groundwater samples. As an example, solid-phase extracts of two groundwater samples taken from a former ammunition destruction site in Switzerland were investigated. 1H NMR spectra of postcolumn SPE enriched compounds, together with accurate mass measurements, allowed the structural elucidation of unknowns. This untargeted approach allowed us to identify expected residues of explosives such as 2,4,6-trinitrotoluene (2,4,6-TNT), Hexogen (RDX) and Octogen (HMX), degradation products of TNT (1,3,5-trinitrobenzene (1,3,5-TNB), 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT), 3,5-dinitrophenol (3,5-DNP), 3,5-dinitroaniline (3,5-DNA), 2,6-dinitroanthranite, and 2-Hydroxy-4,6-dinitrobenzonitrile), benzoic acid, Bisphenol A (a known endocrine disruptor compound), and some toxicologically relevant additives for propelling charges: Centralite I (1,3-diethyl-1,3-diphenylurea), DPU (N,N-diphenylurethane), N,N-diphenylcarbamate (Acardite II), and N-methyl-N-phenylurethane. To our knowledge, this is the first report of the presence of these additives in environmental samples. Extraction recoveries for Centralite I and DPU have been determined. Contaminants identified by our techniques were quantified based on HPLC-UV (HPLC-ultraviolet detection) and 1H NMR mixture analysis. The concentrations of the contaminants ranged between 0.1 and 48 microg/L assuming 100% recovery for the SPE step.

  10. (1)H NMR spectroscopy and chemometrics evaluation of non-thermal processing of orange juice.

    PubMed

    Alves Filho, Elenilson G; Almeida, Francisca D L; Cavalcante, Rosane S; de Brito, Edy S; Cullen, Patrick J; Frias, Jesus M; Bourke, Paula; Fernandes, Fabiano A N; Rodrigues, Sueli

    2016-08-01

    This study evaluated the effect of atmospheric cold plasma and ozone treatments on the key compounds (sugars, amino acids and short chain organic acids) in orange juice by NMR and chemometric analysis. The juice was directly and indirectly exposed to atmospheric cold plasma field at 70kV for different treatment time (15, 30, 45 and 60sec). For ozone processing different loads were evaluated. The Principal Component Analysis shown that the groups of compounds are affected differently depending on the processing. The ozone was the processing that more affected the aromatic compounds and atmospheric cold plasma processing affected more the aliphatic compounds. However, these variations did not result in significant changes in orange juice composition as a whole. Thus, NMR data and chemometrics were suitable to follow quality changes in orange juice processing by atmospheric cold plasma and ozone.

  11. {sup 1}H NMR relaxometry as an indicator of setting and water depletion during cement hydration

    SciTech Connect

    Wang, Biyun; Faure, Paméla; Thiéry, Mickaël; Baroghel-Bouny, Véronique

    2013-03-15

    Proton nuclear magnetic resonance relaxometry has been used to detect setting and microstructure evolution during cement hydration. NMR measurements were performed since casting, during setting and until hardening (from 0 to 3 days). The mobility of water molecules was assessed by an analysis focused on the diagram of longitudinal relaxation time T{sub 1} generated by an Inversion Recovery sequence. The initial stiffening of the solid network was identified by an analysis of the relaxation rate 1/T{sub 1}. The kinetics of water depletion was investigated by using a simple one-pulse acquisition sequence. In parallel, conventional techniques (Vicat needle and temperature monitoring), as well as numerical simulations of hydration, were used to complement and validate these NMR results. Cement pastes and mortars with different water-to-cement ratios made of grey or white OPCs were tested. Furthermore, the effects of the addition of sand, super-plasticizer and silica fume on the hydration kinetics were investigated.

  12. 13C and 1H NMR (Nuclear Magnetic Resonance) studies of solid polyolefines

    NASA Technical Reports Server (NTRS)

    Cudby, M. E. A.; Harris, R. K.; Metcalfe, K.; Packer, K. J.; Smith, P. W. R.

    1983-01-01

    The basis of H-1 and C-13 high-resolution NMR investigations of solid polymers is outlined. The C-13 NMR spectra of solid syndiotactic and isotactic polypropene are discussed and their interpretation in terms of conformation and chain-packing effects are reviewed. The effects of decreasing temperature on the C-13 high-resolution spectrum of an annealed sample of isotactic polypropene is described and interpreted in terms of the crystal structure. The question of the proportion of the sample giving rise to C-13 signals is addressed and some results reported. The main cause for observing only part of the total sample is shown to be the H-1 rotating frame spin-lattice relaxation behavior. The H-1 spin-lattice relaxation and spectral characteristics of a number of polyolefin samples are summarized and the role of spin-diffusion discussed.

  13. Metabolomics in Lung Inflammation: A High Resolution 1H NMR Study of Mice Exposed to Silica Dust

    PubMed Central

    Hu, Jian Zhi; Rommereim, Donald N.; Minard, Kevin R.; Woodstock, Angie; Harrer, Bruce J.; Wind, Robert A.; Phipps, Richard P.; Sime, Patricia J.

    2010-01-01

    Here we report the first 1H NMR metabolomics studies on excised lungs and bronchoalveolar lavage fluid (BALF) from mice exposed to crystalline silica. High resolution 1H NMR metabolic profiling on intact excised lungs was performed using slow magic angle sample spinning (slow-MAS) 1H PASS (phase altered spinning sidebands) at a sample spinning rate of 80 Hz. Metabolic profiling on BALF was completed using fast magic angle spinning at 2kHz. Major findings are that the relative concentrations of choline, phosphocholine (PC) and glycerophosphocholine(GPC) were statistically significantly increased in silica-exposed mice compared to sham controls, indicating an altered membrane choline phospholipids metabolism (MCPM). The relative concentrations of glycogen/glucose, lactate and creatine were also statistically significantly increased in mice exposed to silica dust, suggesting that cellular energy pathways were affected by silica dust. Elevated levels of glycine, lysine, glutamate, proline and 4-hydroxyproline were also increased in exposed mice, suggesting the activation of a collagen pathway. Furthermore, metabolic profiles in mice exposed to silica dust were found to be spatially heterogeneous, in consistent with regional inflammation revealed by in vivo magnetic resonance imaging (MRI). PMID:20020862

  14. 1H NMR study of the phase transitions of trissarcosine calcium chloride single crystals at low temperature

    NASA Astrophysics Data System (ADS)

    Lee, Kyuhong; Lee, Moohee; Lee, Kwang Sei; Lim, Ae Ran

    2005-10-01

    The 1H NMR line-width and spin lattice relaxation time T1 of TSCC single crystals were studied. Variations in the temperature dependence of the spin lattice relaxation time were observed near 65 and 130 K, indicating drastic alterations of the spin dynamics at the phase transition temperatures. The changes in the temperature dependence of T1 near 65 and 130 K correspond to phase transitions of the crystal. The anomalous decrease in T1 around 130 K is due to the critical slowing down of the soft mode. The abrupt change in relaxation time at 65 K is associated with a structural phase transition. The proton spin lattice relaxation time of this crystal also has a minimum value in the vicinity of 185 K, which is governed by the reorientation of the CH3 groups of the sarcosine molecules. From this result, we conclude that the two phase transitions at 65 and 130 K can be discerned from abrupt variations in the 1H NMR relaxation behavior, and that 1H nuclei play important roles in the phase transitions of the TSCC single crystal.

  15. Communication: molecular dynamics and (1)H NMR of n-hexane in liquid crystals.

    PubMed

    Weber, Adrian C J; Burnell, E Elliott; Meerts, W Leo; de Lange, Cornelis A; Dong, Ronald Y; Muccioli, Luca; Pizzirusso, Antonio; Zannoni, Claudio

    2015-07-07

    The NMR spectrum of n-hexane orientationally ordered in the nematic liquid crystal ZLI-1132 is analysed using covariance matrix adaptation evolution strategy (CMA-ES). The spectrum contains over 150 000 transitions, with many sharp features appearing above a broad, underlying background signal that results from the plethora of overlapping transitions from the n-hexane as well as from the liquid crystal. The CMA-ES requires initial search ranges for NMR spectral parameters, notably the direct dipolar couplings. Several sets of such ranges were utilized, including three from MD simulations and others from the modified chord model that is specifically designed to predict hydrocarbon-chain dipolar couplings. In the end, only inaccurate dipolar couplings from an earlier study utilizing proton-proton double quantum 2D-NMR techniques on partially deuterated n-hexane provided the necessary estimates. The precise set of dipolar couplings obtained can now be used to investigate conformational averaging of n-hexane in a nematic environment.

  16. Communication: Molecular dynamics and {sup 1}H NMR of n-hexane in liquid crystals

    SciTech Connect

    Weber, Adrian C. J.; Burnell, E. Elliott; Meerts, W. Leo; Lange, Cornelis A. de; Dong, Ronald Y.; Muccioli, Luca Pizzirusso, Antonio Zannoni, Claudio

    2015-07-07

    The NMR spectrum of n-hexane orientationally ordered in the nematic liquid crystal ZLI-1132 is analysed using covariance matrix adaptation evolution strategy (CMA-ES). The spectrum contains over 150 000 transitions, with many sharp features appearing above a broad, underlying background signal that results from the plethora of overlapping transitions from the n-hexane as well as from the liquid crystal. The CMA-ES requires initial search ranges for NMR spectral parameters, notably the direct dipolar couplings. Several sets of such ranges were utilized, including three from MD simulations and others from the modified chord model that is specifically designed to predict hydrocarbon-chain dipolar couplings. In the end, only inaccurate dipolar couplings from an earlier study utilizing proton-proton double quantum 2D-NMR techniques on partially deuterated n-hexane provided the necessary estimates. The precise set of dipolar couplings obtained can now be used to investigate conformational averaging of n-hexane in a nematic environment.

  17. Degradation Kinetics and Mechanism of Lithospermic Acid under Low Oxygen Condition Using Quantitative 1H NMR with HPLC-MS

    PubMed Central

    Pan, Jianyang; Gong, Xingchu; Qu, Haibin

    2016-01-01

    A novel quantitative 1H NMR (Q-NMR) combined with HPLC-MS method has been proposed for investigating the degradation process of traditional Chinese medicine (TCM) components. Through this method, in-situ monitoring of dynamics degradation process of lithospermic acid (LA), one of the popular polyphenolic acids in TCM, was realized under low oxygen condition. Additionally, this methodology was proved to be simple, rapid and specific. Degradation kinetic runs have been carried out to systematically investigate the effects of two key environmental factors, initial pH values and temperatures. Eight main degradation products of LA were detected, seven of which were tentatively structural elucidated with the help of both NMR and LC-MS in this work and salvianolic acid A (Sal A) was the primary degradation product of LA. A possible degradation pathway of LA was proposed, subsequently. The results showed that the degradation of LA followed pseudo-first-order kinetics. The apparent degradation kinetic constants increased as the initial pH value of the phosphate buffer increased. Under the given conditions, the rate constants of overall degradation as a function of temperature obeyed the Arrhenius equation. Our results proved that the Q-NMR combined with HPLC-MS method can be one of the most promising techniques for investigating degradation process of active components in TCM. PMID:27776128

  18. Classification of Coffee Beans by GC-C-IRMS, GC-MS, and 1H-NMR

    PubMed Central

    Arana, Victoria Andrea; Esseiva, Pierre; Pazos, Diego

    2016-01-01

    In a previous work using 1H-NMR we reported encouraging steps towards the construction of a robust expert system for the discrimination of coffees from Colombia versus nearby countries (Brazil and Peru), to assist the recent protected geographical indication granted to Colombian coffee in 2007. This system relies on fingerprints acquired on a 400 MHz magnet and is thus well suited for small scale random screening of samples obtained at resellers or coffee shops. However, this approach cannot easily be implemented at harbour's installations, due to the elevated operational costs of cryogenic magnets. This limitation implies shipping the samples to the NMR laboratory, making the overall approach slower and thereby more expensive and less attractive for large scale screening at harbours. In this work, we report on our attempt to obtain comparable classification results using alternative techniques that have been reported promising as an alternative to NMR: GC-MS and GC-C-IRMS. Although statistically significant information could be obtained by all three methods, the results show that the quality of the classifiers depends mainly on the number of variables included in the analysis; hence NMR provides an advantage since more molecules are detected to obtain a model with better predictions. PMID:27516919

  19. Identification and quantification of major steviol glycosides in Stevia rebaudiana purified extracts by 1H NMR spectroscopy.

    PubMed

    Pieri, Valerio; Belancic, Andrea; Morales, Susana; Stuppner, Hermann

    2011-05-11

    The use of (1)H NMR spectroscopy for the characterization of Stevia rebaudiana extracts is presented. The developed method allows qualitative and quantitative determination of the major steviol glycosides in purified extracts and fractions obtained from various stages of the purification process. Moreover, it proved to be a powerful tool to differentiate between glycosides which are naturally occurring in the stevia plant and artifacts formed in the course of the manufacturing process. Identification of steviol glycosides was achieved by the use of 2D NMR techniques, whereas quantification is based on qHNMR using anthracene as internal standard. The solvent mixture pyridine-d(5)-DMSO-d(6) (6:1) enabled satisfactory separation of the signals to be integrated. Validation of the method was performed in terms of specificity, precision, accuracy, linearity, robustness, and stability. Quantitative results were compared to those obtained with the JECFA HPLC-UV method and were found to be in reasonable agreement. NMR analysis does not rely on the use of reference compounds and enables significantly faster analysis compared to HPLC-UV. Thus, NMR represents a feasible alternative to HPLC-based methods for the quality control of Stevia rebaudiana extracts.

  20. Combining 1H NMR spectroscopy and multivariate regression techniques to quantitatively determine falsification of porcine heparin with bovine species.

    PubMed

    Monakhova, Yulia B; Diehl, Bernd W K

    2015-11-10

    (1)H NMR spectroscopy was used to distinguish pure porcine heparin and porcine heparin blended with bovine species and to quantify the degree of such adulteration. For multivariate modelling several statistical methods such as partial least squares regression (PLS), ridge regression (RR), stepwise regression with variable selection (SR), stepwise principal component regression (SPCR) were utilized for modeling NMR data of in-house prepared blends (n=80). The models were exhaustively validated using independent test and prediction sets. PLS and RR showed the best performance for estimating heparin falsification regarding its animal origin with the limit of detection (LOD) and root mean square error of validation (RMSEV) below 2% w/w and 1% w/w, respectively. Reproducibility expressed in coefficients of variation was estimated to be below 10% starting from approximately 5% w/w of bovine adulteration. Acceptable calibration model was obtained by SPCR, by its application range was limited, whereas SR is least recommended for heparin matrix. The developed method was found to be applicable also to heparinoid matrix (not purified heparin). In this case root mean square of prediction (RMSEP) and LOD were approximately 7% w/w and 8% w/w, respectively. The simple and cheap NMR method is recommended for screening of heparin animal origin in parallel with official NMR test of heparin authenticity and purity.

  1. Quantification of Human Brain Metabolites from in Vivo1H NMR Magnitude Spectra Using Automated Artificial Neural Network Analysis

    NASA Astrophysics Data System (ADS)

    Hiltunen, Yrjö; Kaartinen, Jouni; Pulkkinen, Juhani; Häkkinen, Anna-Maija; Lundbom, Nina; Kauppinen, Risto A.

    2002-01-01

    Long echo time (TE=270 ms) in vivo proton NMR spectra resembling human brain metabolite patterns were simulated for lineshape fitting (LF) and quantitative artificial neural network (ANN) analyses. A set of experimental in vivo1H NMR spectra were first analyzed by the LF method to match the signal-to-noise ratios and linewidths of simulated spectra to those in the experimental data. The performance of constructed ANNs was compared for the peak area determinations of choline-containing compounds (Cho), total creatine (Cr), and N-acetyl aspartate (NAA) signals using both manually phase-corrected and magnitude spectra as inputs. The peak area data from ANN and LF analyses for simulated spectra yielded high correlation coefficients demonstrating that the peak areas quantified with ANN gave similar results as LF analysis. Thus, a fully automated ANN method based on magnitude spectra has demonstrated potential for quantification of in vivo metabolites from long echo time spectroscopic imaging.

  2. Study of the Cardiotoxicity of Venenum Bufonis in Rats using an 1H NMR-Based Metabolomics Approach

    PubMed Central

    Wang, Junsong; Guo, Pingping; Li, Minghui; Yang, Minghua; Kong, Lingyi

    2015-01-01

    Venenum Bufonis, a well-known traditional Chinese medicine, has been widely used in Asia and has gained popularity in Western countries over the last decade. Venenum Bufonis has obvious side effects that have been observed in clinical settings, but few studies have reported on its cardiotoxicity. In this work, the cardiotoxicity of Venenum Bufonis was investigated using a 11H NMR-based metabolomics approach. The 1H NMR profiles of the serum, myocardial extracts and liver extracts of specific-pathogen-free rats showed that Venenum Bufonis produced significant metabolic perturbations dose-dependently with a distinct time effect, peaking at 2 hr after dosing and attenuating gradually. Clinical chemistry, electrocardiographic recordings, and histopathological evaluation provided additional evidence of Venenum Bufonis-induced cardiac damage that complemented and supported the metabolomics findings. The combined results demonstrated that oxidative stress, mitochondrial dysfunction, and energy metabolism perturbations were associated with the cardiac damage that results from Venenum Bufonis. PMID:25781638

  3. (1)H NMR spectroscopy-guided isolation of new sucrose esters from Physalis alkekengi var. franchetii and their antibacterial activity.

    PubMed

    Zhang, Chuan-Yang; Luo, Jian-Guang; Liu, Rui-Huan; Lin, Ru; Yang, Ming-Hua; Kong, Ling-Yi

    2016-10-01

    Ten new sucrose esters, physakengoses A-J (1-10), were isolated from the aerial parts of Physalis alkekengi var. franchetii under the guidance of (1)H NMR spectroscopy. Their structures were determined by spectroscopic analyses (HRESIMS, 1D and 2D NMR, and ESIMS) and chemical methods. These new compounds were tested for antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. Among them, compounds 2 and 5-8 showed potent inhibitory effects against test strains with MIC values ranging from 3.5 to 14.9μg/mL. These findings may indicate that the P. alkekengi var. franchetii has potential application as an ingredient in pharmaceuticals.

  4. 1H NMR analysis of complexation of hydrotropic agents nicotinamide and caffeine with aromatic biologically active molecules in aqueous solution

    NASA Astrophysics Data System (ADS)

    Lantushenko, Anastasia O.; Mukhina, Yulia V.; Veselkov, Kyrill A.; Davies, David B.; Veselkov, Alexei N.

    2004-07-01

    NMR spectroscopy has been used to elucidate the molecular mechanism of solubilization action of hydrotropic agents nicotinamide (NA) and caffeine (CAF). Hetero-association of NA with riboflavine-mononucleotide (FMN) and CAF with low soluble in aqueous solution synthetic analogue of antibiotic actinomycin D, actinocyl-bis-(3-dimethylaminopropyl) amine (Actill), has been investigated by 500 MHz 1H NMR spectroscopy. Concentration and temperature dependences of proton chemical shifts have been analysed in terms of a statistical-thermodynamic model of indefinite self- and heteroassociation of aromatic molecules. The obtained results enable to conclude that NA-FMN and CAF-Actill intermolecular complexes are mainly stabilized by the stacking interactions of the aromatic chromophores. Hetero-association of the investigated molecules plays an important role in solubilization of aromatic drugs by hydrotropic agents nicotinamide and caffeine.

  5. Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal syringates

    NASA Astrophysics Data System (ADS)

    Świsłocka, Renata

    2013-07-01

    In this work the influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid) was studied. This paper presents spectroscopic vibrations (FT-IR, FT-Raman) and NMR (1H and 13C) study of the series of alkali metal syringates from lithium to cesium syringates. Characteristic shifts of band wavenumbers and changes in band intensities along the metal series were observed. Optimized geometrical structures of the studied compounds were calculated by the B3LYP method using the 6-311++G∗∗ basis set. Aromaticity indices, atomic charges, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and NMR spectra were obtained. The calculated parameters were compared to experimental characteristics of studied compounds.

  6. Two-dimensional sup 1 H NMR studies on HPr protein from Staphylococcus aureus: Complete sequential assignments and secondary structure

    SciTech Connect

    Kalbitzer, H.R.; Neidig, K.P. ); Hengstenberg, W. )

    1991-11-19

    Complete sequence-specific assignments of the {sup 1}H NMR spectrum of HPr protein from Staphylococcus aureus were obtained by two-dimensional NMR methods. Important secondary structure elements that can be derived from the observed nuclear Overhauser effects are a large antiparallel {beta}-pleated sheet consisting of four strands, A, B, C, D, a segment S{sub AB} consisting of an extended region around the active-center histidine (His-15) and an {alpha}-helix, a half-turn between strands B and C, a segment S{sub CD} which shows no typical secondary structure, and the {alpha}-helical, C-terminal segment S{sub term}. These general structural features are similar to those found earlier in HPr proteins from different microorganisms such as Escherichia coli, Bacillus subtilis, and Streptococcus faecalis.

  7. 1H NMR assignments of apo calcyclin and comparative structural analysis with calbindin D9k and S100 beta.

    PubMed Central

    Potts, B. C.; Carlström, G.; Okazaki, K.; Hidaka, H.; Chazin, W. J.

    1996-01-01

    The homodimeric S100 protein calcyclin has been studied in the apo state by two-dimensional 1H NMR spectroscopy. Using a combination of scalar correlation and NOE experiments, sequence-specific 1H NMR assignments were obtained for all but one backbone and > 90% of the side-chain resonances. To our knowledge, the 2 x 90 residue (20 kDa) calcyclin dimer is the largest protein system for which such complete assignments have been made by purely homonuclear methods. Sequential and medium-range NOEs and slowly exchanging backbone amide protons identified directly the four helices and the short antiparallel beta-type interaction between the two binding loops that comprise each subunit of the dimer. Further analysis of NOEs enabled the unambiguous assignment of 556 intrasubunit distance constraints, 24 intrasubunit hydrogen bonding constraints, and 2 x 26 intersubunit distance constraints. The conformation of the monomer subunit was refined by distance geometry and restrained molecular dynamics calculations using the intrasubunit constraints only. Calculation of the dimer structure starting from this conformational ensemble has been reported elsewhere. The extent of structural homology among the apo calcyclin subunit, the monomer subunit of apo S100 beta, and monomeric apo calbindin D9k has been examined in detail by comparing 1H NMR chemical shifts and secondary structures. This analysis was extended to a comprehensive comparison of the three-dimensional structures of the calcyclin monomer subunit and calbindin D9k, which revealed greater similarity in the packing of their hydrophobic cores than was anticipated previously. Together, these results support the hypothesis that all members of the S100 family have similar core structures and similar modes of dimerization. Analysis of the amphiphilicity of Helix IV is used to explain why calbindin D9k is monomeric, but full-length S100 proteins form homodimers. PMID:8931135

  8. Probing phosphorylation by non-mammalian isoprenoid biosynthetic enzymes using (1)H-(31)P-(31)P correlation NMR spectroscopy.

    PubMed

    Majumdar, Ananya; Shah, Meha H; Bitok, J Kipchirchir; Hassis-LeBeau, Maria E; Freel Meyers, Caren L

    2009-09-01

    The biogenesis of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) is accomplished by the methylerythritol phosphate (MEP) pathway in plants, bacteria and parasites, making it a potential target for the development of anti-infective agents and herbicides. The biosynthetic enzymes comprising this pathway catalyze intriguing chemical transformations on diphosphate scaffolds, offering an opportunity to generate novel analogs in this synthetically challenging compound class. Such a biosynthetic approach to generating new diphosphate analogs may involve transformation through discrete diphosphate species, presenting unique challenges in structure determination and characterization of unnatural enzyme-generated diphosphate products produced in tandem. We have developed (1)H-(31)P-(31)P correlation NMR spectroscopy techniques for the direct characterization of crude MEP pathway enzyme products at low concentrations (200 microM to 5 mM) on a room temperature (non-cryogenic) NMR probe. Coupling the 100% natural abundance of the (31)P nucleus with the high intrinsic sensitivity of proton NMR, (1)H-(31)P-(31)P correlation spectroscopy is particularly useful for characterization of unnatural diphosphate enzyme products in the MEP pathway. As proof of principle, we demonstrate the rapid characterization of natural enzyme products of the enzymes IspD, E and F in tandem enzyme incubations. In addition, we have characterized several unnatural enzyme products using this technique, including new products of cytidyltransferase IspD bearing erythritol, glycerol and ribose components. The results of this study indicate that IspD may be a useful biocatalyst and highlight (1)H-(31)P-(31)P correlation spectroscopy as a valuable tool for the characterization of other unnatural products in non-mammalian isoprenoid biosynthesis.

  9. GFT projection NMR for efficient (1)H/ (13)C sugar spin system identification in nucleic acids.

    PubMed

    Atreya, Hanudatta S; Sathyamoorthy, Bharathwaj; Jaipuria, Garima; Beaumont, Victor; Varani, Gabriele; Szyperski, Thomas

    2012-12-01

    A newly implemented G-matrix Fourier transform (GFT) (4,3)D HC(C)CH experiment is presented in conjunction with (4,3)D HCCH to efficiently identify (1)H/(13)C sugar spin systems in (13)C labeled nucleic acids. This experiment enables rapid collection of highly resolved relay 4D HC(C)CH spectral information, that is, shift correlations of (13)C-(1)H groups separated by two carbon bonds. For RNA, (4,3)D HC(C)CH takes advantage of the comparably favorable 1'- and 3'-CH signal dispersion for complete spin system identification including 5'-CH. The (4,3)D HC(C)CH/HCCH based strategy is exemplified for the 30-nucleotide 3'-untranslated region of the pre-mRNA of human U1A protein.

  10. Characterization of various magnesium oxides by XRD and {sup 1}H MAS NMR spectroscopy

    SciTech Connect

    Aramendia, M.A.; Benitez, J.A.; Borau, V.; Jimenez, C.; Marinas, J.M.; Ruiz, J.R.; Urbano, F.

    1999-04-01

    A magnesium oxide obtained by thermal decomposition of commercially available magnesium hydroxide was refluxed in water and acetone in order to improve its chemical and textural properties with the purpose of using it as a support for metals in heterogeneous catalysts. X-ray diffraction, CO{sub 2} chemisorption, and {sup 1}H magic-angle spinning nuclear magnetic resonance were used to identify crystal phases, the number of basic sites, and the nature of OH groups in the oxide, respectively.

  11. Conformation of some N,N'-arylalkyl thioureas by 1H-NMR and infrared spectral analysis

    NASA Astrophysics Data System (ADS)

    Sudha, L. V.; Sathyanarayana, D. N.

    Several N,N'-arylalkyl thioureas were examined with 1H-NMR and i.r. spectra in order to study the conformation of the -NHCSNH- group. The influence of temperature and substituents on the chemical shift of the NH protons has been investigated. Formation of a strong intramolecular hydrogen bond stabilizes the trans—cis conformation for most systems, while for the others the prevalence of different rotational isomers can be postulated. The influence of the steric effect on hydrogen bonding and molecular conformation is discussed.

  12. Hydrogen cluster/network in tobermorite as studied by multiple-quantum spin counting {sup 1}H NMR

    SciTech Connect

    Mogami, Yuuki; Yamazaki, Satoru; Matsuno, Shinya; Matsui, Kunio; Noda, Yasuto; Takegoshi, K.

    2014-12-15

    Proton multiple-quantum (MQ) spin-counting experiment has been employed to study arrangement of hydrogen atoms in 9 Å/11 Å natural/synthetic tobermorites. Even though all tobermorite samples give similar characterless, broad static-powder {sup 1}H NMR spectra, their MQ spin-counting spectra are markedly different; higher quanta in 11 Å tobermorite do not grow with the MQ excitation time, while those in 9 Å one do. A statistical analysis of the MQ results recently proposed [26] is applied to show that hydrogens align in 9 Å tobermorite one dimensionally, while in 11 Å tobermorite they exist as a cluster of 5–8 hydrogen atoms.

  13. 31P{1H}NMR and carbonyl force constants of unsymmetrical bidentate phosphine complexes of group (VI) metal carbonyls

    NASA Astrophysics Data System (ADS)

    Jesu Raj, Joe Gerald; Pathak, Devendra Deo; Kapoor, Pramesh N.

    2015-05-01

    In our present work we report synthesis of an unsymmetrical diphos ligand, 1-diphenylphosphino-2-di-m-tolylphosphinoethane and its coordinate complexes with group (VI) metal carbonyls such as Cr(CO)6 Mo(CO)6 and W(CO)6. The synthesized ligand and its complexes have been completely characterized by elemental analyses, FTIR, 1HNMR, 31P{1H}NMR and FAB mass spectrometry methods. Special emphasis has been given to calculations of carbonyl force constants. Based on the spectroscopic evidences it has been confirmed that these metal carbonyl complexes with the ditertiary phosphine ligand showed cis geometry in their molecular structure.

  14. (1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone.

    PubMed

    Corona, D; Díaz, E; Nava, J L; Guzmán, A; Barrios, H; Fuentes, A; Hernandez-Plata, S A; Allard, J; Jankowski, C K

    2005-11-01

    The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

  15. Discrimination of Apple Liqueurs (Nalewka) Using a Voltammetric Electronic Tongue, UV-Vis and Raman Spectroscopy

    PubMed Central

    Śliwińska, Magdalena; Garcia-Hernandez, Celia; Kościński, Mikołaj; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek; Śliwińska-Bartkowiak, Małgorzata; Jurga, Stefan; Garcia-Cabezon, Cristina; Rodriguez-Mendez, Maria Luz

    2016-01-01

    The capability of a phthalocyanine-based voltammetric electronic tongue to analyze strong alcoholic beverages has been evaluated and compared with the performance of spectroscopic techniques coupled to chemometrics. Nalewka Polish liqueurs prepared from five apple varieties have been used as a model of strong liqueurs. Principal Component Analysis has demonstrated that the best discrimination between liqueurs prepared from different apple varieties is achieved using the e-tongue and UV-Vis spectroscopy. Raman spectra coupled to chemometrics have not been efficient in discriminating liqueurs. The calculated Euclidean distances and the k-Nearest Neighbors algorithm (kNN) confirmed these results. The main advantage of the e-tongue is that, using PLS-1, good correlations have been found simultaneously with the phenolic content measured by the Folin–Ciocalteu method (R2 of 0.97 in calibration and R2 of 0.93 in validation) and also with the density, a marker of the alcoholic content method (R2 of 0.93 in calibration and R2 of 0.88 in validation). UV-Vis coupled with chemometrics has shown good correlations only with the phenolic content (R2 of 0.99 in calibration and R2 of 0.99 in validation) but correlations with the alcoholic content were low. Raman coupled with chemometrics has shown good correlations only with density (R2 of 0.96 in calibration and R2 of 0.85 in validation). In summary, from the three holistic methods evaluated to analyze strong alcoholic liqueurs, the voltammetric electronic tongue using phthalocyanines as sensing elements is superior to Raman or UV-Vis techniques because it shows an excellent discrimination capability and remarkable correlations with both antioxidant capacity and alcoholic content—the most important parameters to be measured in this type of liqueurs.  PMID:27735832

  16. Discrimination of Apple Liqueurs (Nalewka) Using a Voltammetric Electronic Tongue, UV-Vis and Raman Spectroscopy.

    PubMed

    Śliwińska, Magdalena; Garcia-Hernandez, Celia; Kościński, Mikołaj; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek; Śliwińska-Bartkowiak, Małgorzata; Jurga, Stefan; Garcia-Cabezon, Cristina; Rodriguez-Mendez, Maria Luz

    2016-10-09

    The capability of a phthalocyanine-based voltammetric electronic tongue to analyze strong alcoholic beverages has been evaluated and compared with the performance of spectroscopic techniques coupled to chemometrics. Nalewka Polish liqueurs prepared from five apple varieties have been used as a model of strong liqueurs. Principal Component Analysis has demonstrated that the best discrimination between liqueurs prepared from different apple varieties is achieved using the e-tongue and UV-Vis spectroscopy. Raman spectra coupled to chemometrics have not been efficient in discriminating liqueurs. The calculated Euclidean distances and the k-Nearest Neighbors algorithm (kNN) confirmed these results. The main advantage of the e-tongue is that, using PLS-1, good correlations have been found simultaneously with the phenolic content measured by the Folin-Ciocalteu method (R² of 0.97 in calibration and R² of 0.93 in validation) and also with the density, a marker of the alcoholic content method (R² of 0.93 in calibration and R² of 0.88 in validation). UV-Vis coupled with chemometrics has shown good correlations only with the phenolic content (R² of 0.99 in calibration and R² of 0.99 in validation) but correlations with the alcoholic content were low. Raman coupled with chemometrics has shown good correlations only with density (R² of 0.96 in calibration and R² of 0.85 in validation). In summary, from the three holistic methods evaluated to analyze strong alcoholic liqueurs, the voltammetric electronic tongue using phthalocyanines as sensing elements is superior to Raman or UV-Vis techniques because it shows an excellent discrimination capability and remarkable correlations with both antioxidant capacity and alcoholic content-the most important parameters to be measured in this type of liqueurs.

  17. A Raman and UV-Vis study of catecholamines oxidized with Mn(III)

    NASA Astrophysics Data System (ADS)

    Barreto, W. J.; Ponzoni, S.; Sassi, P.

    1998-12-01

    A UV-Vis and Raman spectroscopy study of three aminochromes generated through Mn 3+ oxidation of the dopamine, L-dopa and adrenaline molecules at physiological pH was performed. The UV-Vis spectra of the catecholamines oxidized using Mn 3+ in buffer solution at pH 7.2 show a band at ca. 300 nm, formed by two transitions at 280 nm and 300 nm assigned to an La and Lb transition respectively, and other at ca. 470 nm assigned to an n- π* transition localized in the carbonyl group. This assignment is suggested by the UV-Vis and Raman spectra of ortho-aminoquinone generated by MnO 2 oxidation of a dopamine aqueous acidic solution. The resonance Raman spectra of the three chromes at buffer pH 7.2 show a very similar feature and the most intense bands are observed in the spectral range 1100-1800 cm -1. The band around 1680 cm -1 for the three compounds is assigned to a ν(CO) stretching vibration, 1630 cm -1 to the ν(CC) ring mode, two bands at 1423, 1439 cm -1; 1427, 1438 cm -1 and 1456, 1475 cm -1 are assigned to a ν(CN +) vibration, for aminochrome, dopachrome and adrenochrome, respectively. The excitation profiles for the most intense bands for aminochrome and adrenochrome were obtained. The band assigned to the ν(CN +) present a red shift with respect to the visible band peak, however the band in adrenochrome at 1475 cm -1 shows a profile similar to ν(CO) and ν(CC) modes that reflects the methyl group effect on mixing this mode more effectively with the ν(CC) ring mode.

  18. [Research advances in water quality monitoring technology based on UV-Vis spectrum analysis].

    PubMed

    Wei, Kang-Lin; Wen, Zhi-yu; Wu, Xin; Zhang, Zhong-Wei; Zeng, Tian-Ling

    2011-04-01

    The application of spectral analysis to water quality monitoring is an important developing trend in the field of modern environment monitoring technology. The principle and characteristic of water quality monitoring technology based on UV-Vis spectrum analysis are briefly reviewed. And the research status and advances are introduced from two aspects, on-line monitoring and in-situ monitoring. Moreover, the existent key technical problems are put forward. Finally, the technology trends of multi-parameter water quality monitoring microsystem and microsystem networks based on microspectrometer are prospected, which has certain reference value for the research and development of environmental monitoring technology and modern scientific instrument in the authors' country.

  19. Monitoring of rain events with a submersible UV/VIS spectrophotometer.

    PubMed

    Maribas, Aurélien; Laurent, Nadège; Battaglia, Philippe; do Carmo Lourenço da Silva, Maria; Pons, Marie-Noële; Loison, Bernard

    2008-01-01

    A submersible UV/VIS spectrophotometer has been implemented on the pre-treatment unit of a large-scale wastewater treatment plant (350,000 person-equivalent) to monitor the rapid changes in total Suspended Solids and total Chemical Oxygen Demand occurring during rain events as well as injections of reject water from the sludge treatment train or wasted activated sludge. Calibration has been proven to be difficult for fast composition-varying streams but the device is able to monitor qualitatively sudden quality changes, in spite of the noise affecting the signal.

  20. UV/Vis Action Spectroscopy and Structures of Tyrosine Peptide Cation Radicals in the Gas Phase.

    PubMed

    Viglino, Emilie; Shaffer, Christopher J; Tureček, František

    2016-06-20

    We report the first application of UV/Vis photodissociation action spectroscopy for the structure elucidation of tyrosine peptide cation radicals produced by oxidative intramolecular electron transfer in gas-phase metal complexes. Oxidation of Tyr-Ala-Ala-Ala-Arg (YAAAR) produces Tyr-O radicals by combined electron and proton transfer involving the phenol and carboxyl groups. Oxidation of Ala-Ala-Ala-Tyr-Arg (AAAYR) produces a mixture of cation radicals involving electron abstraction from the Tyr phenol ring and N-terminal amino group in combination with hydrogen-atom transfer from the Cα positions of the peptide backbone.

  1. XRD, lead equivalent and UV-VIS properties study of Ce and Pr lead silicate glasses

    SciTech Connect

    Alias, Nor Hayati Abdullah, Wan Shafie Wan Isa, Norriza Mohd Isa, Muhammad Jamal Md Zali, Nurazila Mat; Abdullah, Nuhaslinda Ee; Muhammad, Azali

    2014-02-12

    In this work, Cerium (Ce) and Praseodymium (Pr) containing lead silicate glasses were produced with 2 different molar ratios low (0.2 wt%) and high (0.4wt%). These types of glasses can satisfy the characteristics required for radiation shielding glasses and minimize the lead composition in glass. The radiation shielding properties of the synthesized glasses is explained in the form of lead equivalent study. The XRD diffraction and UV-VIS analysis were performed to observe the structural changes of the synthesis glasses at 1.5 Gy gamma radiation exposures.

  2. Freeze concentration effects on ice (photo) chemical kinetics investigated by UV-Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Newberg, J. T.; Arble, C.; Zhang, J.

    2013-12-01

    We will describe the setup of a fiber coupled UV-Vis spectrometer to investigate the chemistry and photochemistry of aqueous solutions before and after freezing. The photochemical degradation of pyranine at the isosbestic point was investigated. Direct photochemical degradation was minor compared to indirect degradation through hydroxyl radical (OH) attack at room temperature. At -10 C indirect OH degradation was increased relative to room temperature studies, and has been attributed to the freeze concentration effect. The reaction of bromate with bromide in the presence of acid to form molecular bromine was investigated. Upon freezing the formation rate of bromine significantly increases, which we attribute to the freeze concentration effect.

  3. XRD, lead equivalent and UV-VIS properties study of Ce and Pr lead silicate glasses

    NASA Astrophysics Data System (ADS)

    Alias, Nor Hayati; Abdullah, Wan Shafie Wan; Isa, Norriza Mohd; Isa, Muhammad Jamal Md; Muhammad, Azali; Zali, Nurazila Mat; Abdullah, Nuhaslinda Ee

    2014-02-01

    In this work, Cerium (Ce) and Praseodymium (Pr) containing lead silicate glasses were produced with 2 different molar ratios low (0.2 wt%) and high (0.4wt%). These types of glasses can satisfy the characteristics required for radiation shielding glasses and minimize the lead composition in glass. The radiation shielding properties of the synthesized glasses is explained in the form of lead equivalent study. The XRD diffraction and UV-VIS analysis were performed to observe the structural changes of the synthesis glasses at 1.5 Gy gamma radiation exposures.

  4. A quality control technique based on UV-VIS absorption spectroscopy for tequila distillery factories

    NASA Astrophysics Data System (ADS)

    Barbosa Garcia, O.; Ramos Ortiz, G.; Maldonado, J. L.; Pichardo Molina, J.; Meneses Nava, M. A.; Landgrave, Enrique; Cervantes, M. J.

    2006-02-01

    A low cost technique based on the UV-VIS absorption spectroscopy is presented for the quality control of the spirit drink known as tequila. It is shown that such spectra offer enough information to discriminate a given spirit drink from a group of bottled commercial tequilas. The technique was applied to white tequilas. Contrary to the reference analytic methods, such as chromatography, for this technique neither special personal training nor sophisticated instrumentations is required. By using hand-held instrumentation this technique can be applied in situ during the production process.

  5. The structure of polycaprolactone-clay nanocomposites investigated by 1H NMR relaxometry.

    PubMed

    Monteiro, Mariana S S B; Rodrigues, Claudia Lopes; Neto, Roberto P C; Tavares, Maria Inês Bruno

    2012-09-01

    Nanocomposites based on polycaprolactone (PCL), containing concentrations of 1, 3 and 5 wt% of sodium montmorillonite (NT-25) and organo-modified montmorillonite clay, with three different salts (Viscogel B7, Viscogel S4 and Viscogel B8), were prepared employing the solution intercalation method using chloroform. The PCL nanocomposites were characterized by relaxometry, through determination of the hydrogen spin-lattice relaxation times using low-field nuclear magnetic resonance (NMR). Conventional X-ray diffraction (XDR) was also used to measure the basal space of the nanoclay. The proton spin-lattice relaxation parameters showed that hybrid nanocomposites were formed, containing different parts of intercalated and exfoliated organoclay. The proton T1rhoH also indicated changes in the microstructure, organization and the molecular mobility of the hybrid materials. NMR relaxometry is a good way to evaluate nanomaterials because it provides complementary information, since it is measured in a different time scale. Furthermore, differential scanning calorimetry and thermogravimetric analysis were also used to investigate the crystallization and thermal behavior of the nanocomposites, respectively. All materials had low crystallization temperature (Tc) and the melting temperature (Tm) were very close to that of the PCL matrix, but the degree of crystallinity of the nanocomposites decreased. TGA analysis demonstrated that montmorillonite accelerates PCL's decomposition while unmodified montmorillonite has the opposite effect.

  6. Whole Blood Metabolomics by (1)H NMR Spectroscopy Provides a New Opportunity To Evaluate Coenzymes and Antioxidants.

    PubMed

    Nagana Gowda, G A; Raftery, Daniel

    2017-03-30

    Conventional human blood metabolomics employs serum or plasma and provides a wealth of metabolic information therein. However, this approach lacks the ability to measure and evaluate important metabolites such as coenzymes and antioxidants that are present at high concentrations in red blood cells. As an important alternative to serum/plasma metabolomics, we show here that a simple (1)H NMR experiment can simultaneously measure coenzymes and antioxidants in extracts of whole human blood, in addition to the nearly 70 metabolites that were shown to be quantitated in serum/plasma recently [ Anal. Chem. 2015 , 87 , 706 - 715 ]. Coenzymes of redox reactions: oxidized/reduced nicotinamide adenine dinucleotide (NAD(+) and NADH) and nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH); coenzymes of energy including adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP); and antioxidants, the sum of oxidized and reduced glutathione (GSSG and GSH) can be measured with essentially no additional effort. A new method was developed for detecting many of these unstable species without affecting other blood/blood plasma metabolites. The identities of coenzymes and antioxidants in blood NMR spectra were established combining 1D/2D NMR techniques, chemical shift databases, pH measurements and, finally, spiking with authentic compounds. This is the first study to report identification of major coenzymes and antioxidants and quantify them, simultaneously, with the large pool of other metabolites in human blood using NMR spectroscopy. Considering that the levels of coenzymes and antioxidants represent a sensitive measure of cellular functions in health and numerous diseases, the NMR method presented here potentially opens a new chapter in the metabolomics of blood.

  7. Method development and validation: quantitation of telmisartan bulk drug and its tablet formulation by (1) H NMR spectroscopy.

    PubMed

    Jadeja, Yashwantsinh; Chomal, Bhagyawanti; Patel, Madhavi; Jebaliya, Hetal; Khunt, Ranjan; Shah, Anamik

    2016-12-14

    The quantitative NMR (qNMR) spectroscopy is nowadays a new tool for the determination of pharmaceutical potent biologically active molecules in bulk drug and its tablet formulation than the other analytical techniques. Herein, qNMR method was developed for an anti-hypertensive drug, telmisartan in bulk drug and its tablet formulation. The precise method was developed by using malononitrile as an internal standard. The methylene signal of telmisartan appeared at δ = 5.46 ppm (singlet) relative to the signal of malononitrile at δ = 3.59 ppm (singlet) in CDCl3 , as an NMR solvent. The development and validation of the method were carried out as per International Conference on Harmonization guidelines. The method was found to be linear (r(2)  = 0.9999) for 0.5 to 3.5 mg/ml in the drug concentration range. The relative standard deviation for accuracy and precession was not more than 2.0%. The sensitivity of the method was carried out by limit of detection and a limit of quantification, at 0.05 and 0.2 mg/ml, respectively, concentration. The robustness of the method was studied by changing parameters as well as different solvent manufacturer company. The result shows that method was accurately developed for quantification of telmisartan in pharmaceutical dosage form. The developed method by (1) H NMR spectroscopy is comparatively easy and more precise with respect to the other analytical tools. Copyright © 2016 John Wiley & Sons, Ltd.

  8. 1H-2H cross-polarization NMR in fast spinning solids by adiabatic sweeps

    NASA Astrophysics Data System (ADS)

    Wi, Sungsool; Schurko, Robert; Frydman, Lucio

    2017-03-01

    Cross-polarization (CP) experiments employing frequency-swept radiofrequency (rf) pulses have been successfully used in static spin systems for obtaining broadband signal enhancements. These experiments have been recently extended to heteronuclear I, S = spin-1/2 nuclides under magic-angle spinning (MAS), by applying adiabatic inversion pulses along the S (low-γ) channel while simultaneously applying a conventional spin-locking pulse on the I-channel (1H). This study explores an extension of this adiabatic frequency sweep concept to quadrupolar nuclei, focusing on CP from 1H (I = 1/2) to 2H spins (S = 1) undergoing fast MAS (νr = 60 kHz). A number of new features emerge, including zero- and double-quantum polarization transfer phenomena that depend on the frequency offsets of the swept pulses, the rf pulse powers, and the MAS spinning rate. An additional mechanism found operational in the 1H-2H CP case that was absent in the spin-1/2 counterpart, concerns the onset of a pseudo-static zero-quantum CP mode, driven by a quadrupole-modulated rf/dipolar recoupling term arising under the action of MAS. The best CP conditions found at these fast spinning rates correspond to double-quantum transfers, involving weak 2H rf field strengths. At these easily attainable (ca. 10 kHz) rf field conditions, adiabatic level-crossings among the {|1 ⟩ ,|0 ⟩ ,|-1 ⟩ } mS energy levels, which are known to complicate the CP MAS of quadrupolar nuclei, are avoided. Moreover, the CP line shapes generated in this manner are very close to the ideal 2H MAS spectral line shapes, facilitating the extraction of quadrupolar coupling parameters. All these features were corroborated with experiments on model compounds and justified using numerical simulations and average Hamiltonian theory models. Potential applications of these new phenomena, as well as extensions to higher spins S, are briefly discussed.

  9. Localized 1H NMR spectroscopy in fifty cases of newly diagnosed intracranial tumors

    SciTech Connect

    Demaerel, P.; Johannik, K.; Van Hecke, P.; Van Ongeval, C.; Verellen, S.; Marchal, G.; Wilms, G.; Plets, C.; Goffin, J.; Van Calenbergh, F. )

    1991-01-01

    Fifty patients with newly diagnosed, untreated intracranial tumors were examined with 1H nuclear magnetic resonance single-volume spectroscopy (MRS) using a 1.5 T whole-body MR system. Prior to the MRS, contrast enhanced MR and/or CT imaging studies were carried out. Histological verification was obtained in all patients except one. All tumor spectra revealed distinct abnormalities as compared with the normal brain spectra. Although most meningiomas showed a rather characteristic spectral pattern, generally features specific for the various tumor types were not observed. For instance, though a strong lactic acid signal was seen in most malignant tumors, this signal was also evident in five benign neoplasms.

  10. 1H and 19 F NMR Study of Cation and Anion Motions in Guanidinium Hexafluorozirconate

    NASA Astrophysics Data System (ADS)

    Grottel, M.; Kozak, A.; Pająk, Z.

    1996-09-01

    Proton and fluorine NMR second moments and spin-lattice relaxation times of polycrystalline guanidinium hexafluorozirconate and its deuterated analogue were studied in laboratory (60 MHz) and rotating (H1 = 20 G) frames over a wide range of temperature. An analysis of the experimental results enabled us to reveal a dynamical inequivalence of two crystallographically independent cations and an unexpected high mobility of nonspherical anion dimers. A comparison of the ions dynamics in 2:1 complex studied with the guanidinium 1:1 and 3:1 complexes has shown a significant contribution of the hydrogen bonds to the potential barriers hindering the anion reorientations. At low temperatures a proton motion in the hydrogen bond and at 400 K a solid-solid phase transition have been discerned.

  11. (1)H NMR metabolomics to study the effects of diazepam on anisatin induced convulsive seizures.

    PubMed

    Li, Pei; Wei, Dan-Dan; Wang, Jun-Song; Yang, Ming-Hua; Kong, Ling-Yi

    2016-01-05

    The anticonvulsive properties of diazepam have been extensively studied, mainly focusing on the γ-amino butyrate (GABA) system. The aim of this investigation was to integrally analyze the metabolic events related to neuroprotection of diazepam on anisatin-induced convulsive seizures by a NMR-based metabolomic approach combined with histopathological examination and behavior examination. Multivariate analysis on metabolic profiles of the piriform cortex and cerebellum of mice revealed that diazepam could relieve mice suffering from the convulsive seizures by recovering destructed neurotransmitter and neuromodulator metabolism, ameliorating oxidative stress, alleviating the disturbance in energy, amino acid and nucleic acid metabolism in anisatin intoxicated mice. This integrated metabolomics study provided a powerful and highly effective approach to elucidate therapeutic effects and assessed the safety of diazepam. This study should be helpful for our understanding of convulsive seizures, and provide a holistic view of the treatment effects of benzodiazepine on convulsive seizures.

  12. High-Resolution Microcoil ^1H-NMR for Mass-Limited, Nanoliter-Volume Samples

    NASA Astrophysics Data System (ADS)

    Olson, Dean L.; Peck, Timothy L.; Webb, Andrew G.; Magin, Richard L.; Sweedler, Jonathan V.

    1995-12-01

    High-resolution, proton nuclear magnetic resonance (NMR) spectra of 5-nanoliter samples have been obtained with much higher mass sensitivity [signal-to-noise ratio (S/N) per micromole] than with traditional methods. Arginine and sucrose show a mean sensitivity enhancement of 130 compared to 278-microliter samples run in a 5-millimeter tube in a conventional, commercial probe. This can reduce data acquisition time by a factor of >16,000 or reduce the needed sample mass by a factor of about 130. A linewidth of 0.6 hertz was achieved on a 300-megahertz spectrometer by matching the magnetic susceptibility of the medium that surrounds the detection cell to that of the copper coil. For sucrose, the limit of detection (defined at S/N = 3) was 19 nanograms (56 picomoles) for a 1-minute data acquisition. This technique should prove useful with mass-limited samples and for use as a detector in capillary separations.

  13. Molecular degradation of ancient documents revealed by 1H HR-MAS NMR spectroscopy

    PubMed Central

    Corsaro, Carmelo; Mallamace, Domenico; Łojewska, Joanna; Mallamace, Francesco; Pietronero, Luciano; Missori, Mauro

    2013-01-01

    For centuries mankind has stored its knowledge on paper, a remarkable biomaterial made of natural cellulose fibers. However, spontaneous cellulose degradation phenomena weaken and discolorate paper over time. The detailed knowledge of products arising from cellulose degradation is essential in understanding deterioration pathways and in improving durability of cultural heritage. In this study, for the first time, products of cellulose degradation were individually detected in solid paper samples by means of an extremely powerful proton HR-MAS NMR set-up, in combination to a wise use of both ancient and, as reference, artificially aged paper samples. Carboxylic acids, in addition to more complex dicarboxylic and hydroxy-carboxylic acids, were found in all samples studied. Since these products can catalyze further degradation, their knowledge is fundamental to improve conservation strategies of historical documents. Furthermore, the identification of compounds used in ancient production techniques, also suggests for artifacts dating, authentication and provenance. PMID:24104201

  14. Urea's effect on the ribonuclease A catalytic efficiency: a kinetic, 1H NMR and molecular orbital study.

    PubMed

    Almarza, Jorge; Rincón, Luis; Bahsas, Alí; Pinto, María Angela; Brito, Francisco

    2013-02-01

    Understanding of protein-urea interactions is one of the greatest challenges to modern structural protein chemistry. Based in enzyme kinetics experiments and (1)H NMR spectroscopic analysis we proposed that urea, at low concentrations, directly interacts with the protonated histidines of the active center of RNase A, following a simple model of competitive inhibition. These results were supported by theoretical analysis based on the frontier molecular orbital theory and suggest that urea might establish a favorable interaction with the cationic amino acids. Our experimental evidence and theoretical analysis indicate that the initials steps of the molecular mechanism of Urea-RNase A interaction passes through the establishment of a three center four electron adduct. Also, our results would explain the observed disruption of the (1)H NMR signals corresponding to H12 and H119 (involved in catalysis) of the RNase A studied in the presence of urea. Our interaction model of urea-amino acids (cationic) can be extended to explain the inactivation of other enzymes with cationic amino acids at the active site.

  15. Correlation of tryptophan fluorescence intensity decay parameters with sup 1 H NMR-determined rotamer conformations: (tryptophan sup 2 )oxytocin

    SciTech Connect

    Ross, J.B.A.; Schwartz, G.P.; Laws, W.R. ); Wyssbrod, H.R.; Porter, R.A. ); Michaels, C.A. )

    1992-02-18

    While the fluorescence decay kinetics of tyrosine model compounds can be explained in terms of heterogeneity derived from the three ground-state {chi}{sup 1} rotamers, a similar correlation has yet to be directly observed for a tryptophan residue. In addition, the asymmetric indole ring might also lead to heterogeneity from {chi}{sup 2} rotations. In this paper, the time-resolved and steady-state fluorescence properties of (tryptophan{sup 2})oxytocin at pH 3 are presented and compared with {sup 1}H NMR results. According to the unrestricted analyses of individual fluorescence decay curves taken as a function of emission wavelength-independent decay constants, only three exponential terms are required. In addition, the preexponential weighting factors (amplitudes) have the same relative relationship (weights) as the {sup 1}H NMR-determined {chi}{sup 1} rotamer populations of the indole side chain. {sup 15}N was used in heteronuclear coupling experiments to confirm the rotamer assignments. Inclusion of a linked function restricting the decay amplitudes to the {chi}{sup 1} rotamer populations in the individual decay curve analyses and in the global analysis confirms this correlation. According to qualitative nuclear Overhauser data, there are two {chi}{sup 2} populations.

  16. Analysis of the electronic, IR, and 1H NMR spectra of conjugated oligomers based on 4,4'-triphenylamine vinylene

    NASA Astrophysics Data System (ADS)

    Baryshnikov, G. V.; Minaeva, V. A.; Minaev, B. F.; Sun, V.-H.; Grigoras, M.

    2016-09-01

    Two types of conjugated oligomers based on 4,4'-triphenylamine vinylene have been synthesized and characterized by the methods of IR, UV-visible, and 1H NMR spectroscopy. The corresponding spectra have also been simulated theoretically at the density functional theory level with application of the B3LYP and BMK hybrid exchange-correlation functionals. A comparative analysis of the experimental and theoretical spectra of polymers and oligomers has revealed regularities of the manifestation of spectral signals depending on the conjugation chain length and the presence of a substituent in the triphenylamine core. It has been established, in particular, that the absolute intensity of IR bands satisfies a linear dependence with increase in the degree of polymerization; however, no frequency shift is observed at the same time. The position of the main peak in electron absorption spectra demonstrates the bathochromic shift with an increase in the oligomeric chain length due to the narrowing of the energy gap between the boundary molecular orbitals. Based on the theoretical estimation of the hydrogen atoms chemical shifts, the signals of various protons types in the strongly broadened experimental 1H NMR spectra of the bis-(4-iodine phenyl)-phenylamine and N,N-bis-(4-iodine phenyl)-4'-(phenylethynyl)-phenylamine polymerization products have also been identified.

  17. (1)H NMR-based metabolomics of Daphnia magna responses after sub-lethal exposure to triclosan, carbamazepine and ibuprofen.

    PubMed

    Kovacevic, Vera; Simpson, André J; Simpson, Myrna J

    2016-09-01

    Pharmaceuticals and personal care products are a class of emerging contaminants that are present in wastewater effluents, surface water, and groundwater around the world. There is a need to determine rapid and reliable bioindicators of exposure and the toxic mode of action of these contaminants to aquatic organisms. (1)H nuclear magnetic resonance (NMR)-based metabolomics in combination with multivariate statistical analysis was used to determine the metabolic profile of Daphnia magna after exposure to a range of sub-lethal concentrations of triclosan (6.25-100μg/L), carbamazepine (1.75-14mg/L) and ibuprofen (1.75-14mg/L) for 48h. Sub-lethal triclosan exposure suggested a general oxidative stress condition and the branched-chain amino acids, glutamine, glutamate, and methionine emerged as potential bioindicators. The aromatic amino acids, serine, glycine and alanine are potential bioindicators for sub-lethal carbamazepine exposure that may have altered energy metabolism. The potential bioindicators for sub-lethal ibuprofen exposure are serine, methionine, lysine, arginine and leucine, which showed a concentration-dependent response. The differences in the metabolic changes were related to the dissimilar modes of toxicity of triclosan, carbamazepine and ibuprofen. (1)H NMR-based metabolomics gave an improved understanding of how these emerging contaminants impact the keystone species D. magna.

  18. (1)H NMR at Larmor frequencies down to 3Hz by means of Field-Cycling techniques.

    PubMed

    Kresse, B; Becher, M; Privalov, A F; Hofmann, M; Rössler, E A; Vogel, M; Fujara, F

    2017-04-01

    Field-Cycling (FC) NMR experiments were carried out at (1)H Larmor frequencies down to about 3Hz. This could be achieved by fast switching a high polarizing magnetic field down to a low evolution field which is tilted with respect to the polarization field. Then, the low frequency Larmor precession of the nuclear spin magnetization about this evolution field is registered by means of FIDs in a high detection field. The crucial technical point of the experiment is the stabilization of the evolution field, which is achieved by compensating for temporal magnetic field fluctuations of all three spatial components. The paper reports on some other basic low field experiments such as the simultaneous measurement of the Larmor frequency and the spin-lattice relaxation time in such small fields as well as the irradiation of oscillating transversal magnetic field pulses at very low frequencies as a novel method for field calibration in low field FC NMR. The potential of low field FC is exemplified by the (1)H relaxation dispersion of water at frequencies below about 2kHz stemming from the slow proton exchange process.

  19. Adsorption mechanism at the molecular level between polymers and uremic octapeptide by the 2D 1H NMR Technique.

    PubMed

    Li, Guohua; Li, Jihong; Wang, Wei; Yang, Mei; Zhang, Yuanwei; Sun, Pingchuan; Yuan, Zhi; He, Binglin; Yu, Yaoting

    2006-06-01

    To remove uremic octapeptide from the blood stream of uremic patients, various modified polyacylamide cross-linked absorbents were prepared. Adsorption experiments showed these absorbents have significant differences in adsorption capacity to the target peptide. In this paper, two-dimension proton nuclear magnetic resonance (2D 1H NMR) spectroscopy was used to investigate the interaction mechanism between the peptide and the adsorbents. Because of the insolubility of the absorbent, some soluble linear polymers with the same functional groups as the absorbents were employed as the model adsorbents in 2D 1H NMR. The preferred binding site for the peptide and polymers was identified to be at the C-terminal carboxyl group of the octapeptide via chemical shift perturbation effects. In this study, we found that hydrogen bonding, electrostatic, and hydrophobic interactions all play a role in the interaction force but had different contributions. Especially, the great chemical shift changes of the aromatic amino acid residues (Trp) during the interaction between butyl-modified polyacrylamide and octapeptide suggested the hydrophobic interaction, incorporated with the electrostatic force, played an important role in the binding reaction in aqueous solutions. This information not only rationally explained the results of the adsorption experiments, but also identified the effective binding site and mechanism, and shall provide a structural basis for designing better affinity-type adsorbents for the target peptide.

  20. Regression formulas for density functional theory calculated 1H and 13C NMR chemical shifts in toluene-d8.

    PubMed

    Konstantinov, Ivan A; Broadbelt, Linda J

    2011-11-10

    This study aimed at investigating the performance of a series of basis sets, density functional theory (DFT) functionals, and the IEF-PCM solvation model in the accurate calculation of (1)H and (13)C NMR chemical shifts in toluene-d(8). We demonstrated that, on a test set of 37 organic species with various functional moieties, linear scaling significantly improved the calculated shifts and was necessary to obtain more accurate results. Inclusion of a solvation model produced larger deviations from the experimental data as compared to the gas-phase calculations. Moreover, we did not find any evidence that very large basis sets were necessary to reproduce the experimental NMR data. Ultimately, we recommend the use of the BMK functional. For the (1)H shifts the use of the 6-311G(d) basis set gave linearly scaled mean unsigned (MU) and root-mean-square (rms) errors of 0.15 ppm and 0.21 ppm, respectively. For the calculation of the (13)C chemical shifts the 6-31G(d) basis set produced MUE of 1.82 ppm and RMSE of 3.29 ppm.

  1. LC-MS- and (1)H NMR Spectroscopy-Guided Identification of Antifungal Diterpenoids from Sagittaria latifolia.

    PubMed

    Ravu, Ranga Rao; Jacob, Melissa R; Jeffries, Cynthia; Tu, Ying; Khan, Shabana I; Agarwal, Ameeta K; Guy, R Kiplin; Walker, Larry A; Clark, Alice M; Li, Xing-Cong

    2015-09-25

    Antifungal screening of small-molecule natural product libraries showed that a column fraction (CF) derived from the plant extract of Sagittaria latifolia was active against the fungal pathogen Cryptococcus neoformans. Dereplication analysis by liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy ((1)H NMR) indicated the presence of new compounds in this CF. Subsequent fractionation of the plant extract resulted in the identification of two new isopimaradiene-type diterpenoids, 1 and 2. The structures of 1 and 2 were determined by chemical methods and spectroscopic analysis as isopimara-7,15-dien-19-ol 19-O-α-l-arabinofuranoside and isopimara-7,15-dien-19-ol 19-O-α-l-(5'-acetoxy)arabinofuranoside, respectively. Compound 1 exhibited IC50 values of 3.7 and 1.8 μg/mL, respectively, against C. neoformans and C. gattii. Its aglycone, isopimara-7,15-dien-19-ol (3), resulting from acid hydrolysis of 1, was also active against the two fungal pathogens, with IC50 values of 9.2 and 6.8 μg/mL, respectively. This study demonstrates that utilization of the combined LC-MS and (1)H NMR analytical tools is an improved chemical screening approach for hit prioritization in natural product drug discovery.

  2. Development and Validation of Quantitative (1)H NMR Spectroscopy for the Determination of Total Phytosterols in the Marine Seaweed Sargassum.

    PubMed

    Zhang, Xiu-Li; Wang, Cong; Chen, Zhen; Zhang, Pei-Yu; Liu, Hong-Bing

    2016-08-10

    Knowledge of phytosterol (PS) contents in marine algae is currently lacking compared to those in terrestrial plants. The present studies developed a quantitative (1)H NMR method for the determination of the total PSs in Sargassum. The characteristic proton signal H-3α in PSs was used for quantification, and 2,3,4,5-tetrachloro-nitrobenzene was used as an internal standard. Seaweed samples could be recorded directly after total lipid extraction and saponification. The results showed that the PS contents in Sargassum fusiforme (788.89-2878.67 mg/kg) were significantly higher than those in Sargassum pallidum (585.33-1596.00 mg/kg). The variable contents in both species suggested that fixed raw materials are very important for future research and development. Orthogonal projection to latent structures discriminant analysis was carried out in the spectral region of δ 3.00-6.50 in the (1)H NMR spectrum. S. fusiforme and S. pallidum could be separated well, and the key sterol marker was fucosterol.

  3. Effect of 1,10-phenanthroline aromaticity in carboxylic acids:1H NMR spectroscopy, GIAO calculations and thermodynamic properties

    NASA Astrophysics Data System (ADS)

    Machado, Camila M. B.; Santos, Vanessa F. C.; Belarmino, Marcia K. D. L.; França, José A. A.; Moura, Gustavo L. C.; Lima, Nathalia B. D.

    2016-08-01

    Hydrogen bonding represents a class of chemical interactions, which are directly responsible for several physical properties, such as: energetic stabilities, boiling points, vibrational modes, bond lengths, etc. In this article, we examine from the point of view of 1H NMR spectroscopy and GIAO calculations, the effects associated with the process of formation of the hydrogen bonds as they appear in the chemical shifts of the acidic hydrogens in the complexes between nitrogenated compounds, PHEN, BIPY and DIBIPY, and carboxylic acids, HOOCH, HOOCCH3 and HOOCC6H5. All computational simulations were performed using the quantum chemical methods B3LYP/6-31++G(d,p) and ωB97X-D/def2-TZVP. The 1H NMR spectroscopy results showed that, in both cases, the hydrogen nucleus of the OH group is the most affected in the process of hydrogen bond formation. For the complexes involving PHEN we observed that the hydrogen nucleus is more strongly shielded when compared with this signal in the corresponding complexes involving BIPY and DIBIPY.

  4. The effect of standardized food intake on the association between BMI and 1H-NMR metabolites

    PubMed Central

    Schutte, Bianca A. M.; van den Akker, Erik B.; Deelen, Joris; van de Rest, Ondine; van Heemst, Diana; Feskens, Edith J. M.; Beekman, Marian; Slagboom, P. Eline

    2016-01-01

    Multiple studies have shown that levels of 1H-NMR metabolites are associated with disease and risk factors of disease such as BMI. While most previous investigations have been performed in fasting samples, meta-analysis often includes both cohorts with fasting and non-fasting blood samples. In the present study comprising 153 participants (mean age 63 years; mean BMI 27 kg/m2) we analyzed the effect of a standardized liquid meal (SLM) on metabolite levels and how the SLM influenced the association between metabolites and BMI. We observed that many metabolites, including glycolysis related metabolites, multiple amino acids, LDL diameter, VLDL and HDL lipid concentration changed within 35 minutes after a standardized liquid meal (SLM), similarly for all individuals. Remarkable, however, is that the correlations of metabolite levels with BMI remained highly similar before and after the SLM. Hence, as exemplified with the disease risk factor BMI, our results suggest that the applicability of 1H-NMR metabolites as disease biomarkers depends on the standardization of the fasting status rather than on the fasting status itself. Future studies are required to investigate the dependency of metabolite biomarkers for other disease risk factors on the fasting status. PMID:27966583

  5. 1H, 13C NMR and DFT Study of Hydrogen Bonding in Imidazolium-based Ionic Liquids.

    PubMed

    Balevičius, Vytautas; Gdaniec, Zofia; Džiaugys, Lukas; Kuliešius, Feliksas; Maršalka, Arūnas

    2011-09-01

    The ionic liquid 1-decyl-3-methyl-imidazolium bromide [C10mim][Br], the neat material, and also dissolved (~0.01 mole fraction) in various dielectric media (acetonitrile, benzene, chloroform, dichloromethane, methanol, 2-butanol and H2O) was studied using 1H and 13C NMR spectroscopy. The most important interaction in this compound is considered to be the Br-...H-C2+ hydrogen bond, which is formed between the anions and cations. The obtained results show that dielectric medium influence mostly the behavior of the Br-...H-C2+ bridge proton. The changes observed in 1H and 13C NMR spectra of [C10mim][Br] with increasing solvents polarity and temperature can be explained applying the model of the lengthening of the H2...Br- bond with the accompanying thickening of the solvation shell of bromine anion and C2-H bond contraction. The short-range order effects related to the configuration of neighboring dipoles of solvent molecules are more important for the solvation ability of small anions than the bulk solvent field effect. However, the solvents, molecules of which tend to associate via hydrogen bonding, can significantly affect the dynamics of anions.

  6. (1)H NMR and GC-MS based metabolomics reveal nano-Cu altered cucumber (Cucumis sativus) fruit nutritional supply.

    PubMed

    Zhao, Lijuan; Hu, Jerry; Huang, Yuxiong; Wang, Hongtao; Adeleye, Adeyemi; Ortiz, Cruz; Keller, Arturo A

    2017-01-01

    It is imperative to study the interaction of nanoparticles residuals with crop plants in agricultural soils, due to the increased application of nanotechnology in agriculture. So far, a few studies have focused on the impact of nanoparticles on fruit quality and nutritional supply. In this work, a thorough and comprehensive analysis of metabolite changes of cucumber fruits from plants under nano-Cu stress was possible through the use of both (1)H NMR and GC-MS. The results of supervised partial least-squares discriminant analysis from both platforms showed that cucumber fruit extracts samples were clearly grouped based on the nano-Cu level in soil. This indicates that the fruit metabolite profile was influenced by exposure to nano-Cu. GC-MS data showed concentrations of some sugars, organic acids, amino acids, and fatty acids were increased or decreased by nano-Cu. Several metabolites, such as methylnicotinamide (MNA), trigonelline, imidazole, quinolinate were only detected and quantified by (1)H NMR. Our results showed that combining the two platforms provided a comprehensive understanding about the metabolites (nutrient supply) changes in cucumber fruits impacted by exposure to nano-Cu.

  7. Metabolic fingerprinting of Leontopodium species (Asteraceae) by means of 1H NMR and HPLC–ESI-MS

    PubMed Central

    Safer, Stefan; Cicek, Serhat S.; Pieri, Valerio; Schwaiger, Stefan; Schneider, Peter; Wissemann, Volker; Stuppner, Hermann

    2011-01-01

    The genus Leontopodium, mainly distributed in Central and Eastern Asia, consists of ca. 34–58 different species. The European Leontopodium alpinum, commonly known as Edelweiss, has a long tradition in folk medicine. Recent research has resulted in the identification of prior unknown secondary metabolites, some of them with interesting biological activities. Despite this, nearly nothing is known about the Asian species of the genus. In this study, we applied proton nuclear magnetic resonance (1H NMR) spectroscopy and liquid chromatography–mass spectrometry (LC–MS) metabolic fingerprinting to reveal insights into the metabolic patterns of 11 different Leontopodium species, and to conclude on their taxonomic relationship. Principal component analysis (PCA) of 1H NMR fingerprints revealed two species groups. Discriminators for these groups were identified as fatty acids and sucrose for group A, and ent-kaurenoic acid and derivatives thereof for group B. Five diterpenes together with one sesquiterpene were isolated from Leontopodium franchetii roots; the compounds were described for the first time for L. franchetii: ent-kaur-16-en-19-oic acid, methyl-15α-angeloyloxy-ent-kaur-16-en-19-oate, methyl-ent-kaur-16-en-19-oate, 8-acetoxymodhephene, 19-acetoxy-ent-kaur-16-ene, methyl-15β–angeloyloxy-16,17-epoxy-ent-kauran-19-oate. In addition, differences in the metabolic profile between collected and cultivated species could be observed using a partial least squares-discriminant analysis (PLS-DA). PCA of the LC–MS fingerprints revealed three groups. Discriminating signals were compared to literature data and identified as two bisabolane derivatives responsible for discrimination of group A and C, and one ent-kaurenoic acid derivative, discriminating group B. A taxonomic relationship between a previously unidentified species and L. franchetii and Leontopodium sinense could be determined by comparing NMR fingerprints. This finding supports recent molecular data

  8. Differentiation of tea varieties using UV-Vis spectra and pattern recognition techniques

    NASA Astrophysics Data System (ADS)

    Palacios-Morillo, Ana; Alcázar, Ángela.; de Pablos, Fernando; Jurado, José Marcos

    2013-02-01

    Tea, one of the most consumed beverages all over the world, is of great importance in the economies of a number of countries. Several methods have been developed to classify tea varieties or origins based in pattern recognition techniques applied to chemical data, such as metal profile, amino acids, catechins and volatile compounds. Some of these analytical methods become tedious and expensive to be applied in routine works. The use of UV-Vis spectral data as discriminant variables, highly influenced by the chemical composition, can be an alternative to these methods. UV-Vis spectra of methanol-water extracts of tea have been obtained in the interval 250-800 nm. Absorbances have been used as input variables. Principal component analysis was used to reduce the number of variables and several pattern recognition methods, such as linear discriminant analysis, support vector machines and artificial neural networks, have been applied in order to differentiate the most common tea varieties. A successful classification model was built by combining principal component analysis and multilayer perceptron artificial neural networks, allowing the differentiation between tea varieties. This rapid and simple methodology can be applied to solve classification problems in food industry saving economic resources.

  9. Standardized UV-vis spectra as the foundation for a threshold-based, integrated photosafety evaluation.

    PubMed

    Bauer, Daniel; Averett, Lacey A; De Smedt, Ann; Kleinman, Mark H; Muster, Wolfgang; Pettersen, Betty A; Robles, Catherine

    2014-02-01

    Phototoxicity is a relatively common phenomenon and is an adverse effect of some systemic drugs. The fundamental initial step of photochemical reactivity is absorption of a photon; however, little guidance has been provided thus far regarding how ultraviolet-visible (UV-vis) light absorption spectra may be used to inform testing strategies for investigational drugs. Here we report the results of an inter-laboratory study comparing the data from harmonized UV-vis light absorption spectra obtained in methanol with data from the in vitro 3T3 Neutral Red Uptake Phototoxicity Test. Six pharmaceutical companies submitted data according to predefined quality criteria for 76 compounds covering a wide range of chemical classes showing a diverse but "positive"-enhanced distribution of photo irritation factors (22%: PIF<2, 12%: PIF 2-5, 66%: PIF>5). For compounds being formally positive (PIF value above 5) the lowest reported molar extinction coefficient (MEC) was 1700 L mol⁻¹ cm⁻¹ in methanol. However, the majority of these formally positive compounds showed MEC values being significantly higher (up to almost 40,000 L mol⁻¹ cm⁻¹). In conclusion, an MEC value of 1000 L mol⁻¹ cm⁻¹ may represent a reasonable and pragmatic threshold warranting further experimental photosafety evaluation.

  10. UV/VIS liquid-core optical fiber long lightpath absorption system for spectrophotometer

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Wu, Guanyan; Xu, Zheng; Liao, Yuanmin; He, Qushe; Wang, Jufang; Feng, Mingzhao

    1998-08-01

    A new type of UV/VIS liquid-core optical fiber long lightpath absorption system, which was designed as an accessory and spectrum range was extended to UV with minimum wavelength 220 micrometer to compatible with conventional UV/VIS spectrophotometer, was described with high assembling precision RSD 1.4% and absorption 1 to approximately 700 cm for choice. The coupling between source light radiation and liquid-core optical fiber was tested and optimum condition was obtained. The samples introduction was presented and UV transmission spectra of optical fiber was detected. The system was applied to detect elements Cd(II), Pd(II), F-1, Cr(VI), Cu(II), Fe(II), Ti(IV), Pt(II) and medicines Carbamazipine and Vitamin E by using of 105 cm long LCOF, and sensitivities were 42 to approximately 158 times as much as those by 1 cm conventional cell in length, detection limits (3(sigma) ) 0.14 to approximately 17 ng/ml, relative errors less than 11.2%, and recoveries 94 to approximately 102%.

  11. The UV/Vis absorption spectrum of matrix-isolated dichlorine peroxide, ClOOCl.

    PubMed

    von Hobe, Marc; Stroh, Fred; Beckers, Helmut; Benter, Thorsten; Willner, Helge

    2009-03-14

    UV/Vis absorption spectra of ClOOCl isolated in neon matrices were measured in the wavelength range 220-400 nm. The purity of the trapped samples was checked by infrared and UV/Vis matrix spectroscopy as well as low-temperature Raman spectroscopy. At wavelengths below 290 nm, the results agree with the UV spectrum recently published by Pope et al. [J. Phys. Chem. A, 2007, 111, 4322-4332]. However, the observed absorption in the long wavelength tail of the spectrum-relevant for polar stratospheric ozone loss-is substantially higher than reported by Pope et al. Our results suggest the existence of a ClOOCl electronic state manifold leading to an absorption band similar to those of the near UV spectrum of Cl(2). The differences to previous studies can be accounted for quantitatively by contributions to the reported absorption spectra caused by impurities. The observed band in the long wavelength tail is supported by several high-level ab initio calculations. However, questions arise concerning absolute values of the ClOOCl cross sections, an issue that needs to be revisited in future studies. With calculated photolysis rates based on our spectrum scaled to previous cross sections at the peak absorption, the known polar catalytic ozone-destruction cycles to a large extent account for the observed ozone depletion in the spring polar stratosphere.

  12. TiO2/WO3 photoactive bilayers in the UV-Vis light region

    NASA Astrophysics Data System (ADS)

    Vasilaki, E.; Vernardou, D.; Kenanakis, G.; Vamvakaki, M.; Katsarakis, N.

    2017-04-01

    In this work, photoactive bilayered films consisting of anatase TiO2 and monoclinic WO3 were synthesized by a sol-gel route. Titanium isopropoxide and tungsten hexachloride were used as metal precursors and deposition was achieved by spin-coating on Corning glass substrates. The samples were characterized by X-ray diffraction, photoluminescence, UV-Vis, and Raman spectroscopy, as well as field emission scanning electron microscopy. The prepared immobilized catalysts were tested for their photocatalytic performance by the decolorization of methylene blue in aqueous matrices, under UV-Vis light irradiation. The annealing process influenced the crystallinity of the bilayered films, while the concentration of the tungsten precursor solution and the position of the tungsten trioxide layer further affected their photocatalytic performance. In particular, the photocatalytic performance of the bilayered films was optimized at a concentration of 0.1 M of the WO3 precursor solution, when deposited as an overlying layer on TiO2 by two annealing steps ( 76% methylene blue decolorization in 300 min of irradiation versus 59% in the case of a bare TiO2 film). In general, the coupled layer catalysts exhibited superior photoactivity compared to that of bare TiO2 films with WO3 acting as an electron trap, resulting, therefore, in a more efficient electron-hole separation and inhibiting their recombination.

  13. SANS and UV-vis spectroscopy studies of resultant structure from lysozyme adsorption on silica nanoparticles.

    PubMed

    Kumar, Sugam; Aswal, Vinod K; Kohlbrecher, Joachim

    2011-08-16

    The interaction of lysozyme protein (M.W. 14.7 kD) with two sizes of silica nanoparticles (16 and 25 nm) has been examined in aqueous solution using UV-vis spectroscopy and small-angle neutron scattering (SANS). The measurements were performed on fixed concentration (1 wt %) of nanoparticles and varying concentration of protein in the range 0 to 2 wt %. The adsorption isotherm as obtained using UV-vis spectroscopy suggests strong interaction of the two components and shows an exponential behavior. The saturation values of adsorption are found to be around 90 and 270 protein molecules per particle for 16 and 25 nm sized nanoparticles, respectively. The adsorption of protein on nanoparticles leads to the aggregation of particles and these structures have been studied by SANS. The aggregates are characterized by fractal structure coexisting with unaggregated particles at low protein concentrations and free proteins at higher protein concentrations. Further, contrast variation SANS measurements have been carried out to differentiate the adsorbed and free protein in these systems.

  14. Characterization of cytochrome c as marker for retinal cell degeneration by uv/vis spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Hollmach, Julia; Schweizer, Julia; Steiner, Gerald; Knels, Lilla; Funk, Richard H. W.; Thalheim, Silko; Koch, Edmund

    2011-07-01

    Retinal diseases like age-related macular degeneration have become an important cause of visual loss depending on increasing life expectancy and lifestyle habits. Due to the fact that no satisfying treatment exists, early diagnosis and prevention are the only possibilities to stop the degeneration. The protein cytochrome c (cyt c) is a suitable marker for degeneration processes and apoptosis because it is a part of the respiratory chain and involved in the apoptotic pathway. The determination of the local distribution and oxidative state of cyt c in living cells allows the characterization of cell degeneration processes. Since cyt c exhibits characteristic absorption bands between 400 and 650 nm wavelength, uv/vis in situ spectroscopic imaging was used for its characterization in retinal ganglion cells. The large amount of data, consisting of spatial and spectral information, was processed by multivariate data analysis. The challenge consists in the identification of the molecular information of cyt c. Baseline correction, principle component analysis (PCA) and cluster analysis (CA) were performed in order to identify cyt c within the spectral dataset. The combination of PCA and CA reveals cyt c and its oxidative state. The results demonstrate that uv/vis spectroscopic imaging in conjunction with sophisticated multivariate methods is a suitable tool to characterize cyt c under in situ conditions.

  15. A Study of Photoluminiscence and UV-Vis in Enhanced GaN Nanofibers

    NASA Astrophysics Data System (ADS)

    Robles-Garcia, Joshua; Melendez-Zambrana, Anamaris; Ramos, Idalia

    2014-03-01

    The photoluminiscence (PL) and UV-Vis properties of Gallium Nitride (GaN) nanofibers were investigated for samples fabricated with a precursor solution containing Gallium Nitrate Hydrate, Cellulose Acetate, and Urea in the solvents Dimethylacetamide (DMA) and Acetone. GaN is a wide bandgap (3.4 eV) semiconductor that can be used in a variety of applications including solid-state lighting, high power, and high frequency devices. In previous work, we produced polycrystalline GaN nanofibers with wurtzite structure, using the electrospinning method and a thermal treatment in nitrogen and ammonia at 1000C. In this research we study the addition of urea to the precursor solution to enhance the crystallinity of the fibers at lower sintering temperatures. The molar ratios of urea added to the precursor range from 0 to 1.7 M. After electrospinning the fibers were sintered in Nitrogen at 450C for 3 hours and then, under ammonia gas flow at 900C for 5 hours. X-Ray Diffraction (XRD), UV-Vis spectroscopy, and PL measurements at room temperature were used to study the structural and optical properties of the fibers during the sintering process. This work was sponsored by UPRH PREM (NSF-DMR-0934195).

  16. Experimental and theoretical studies on IR, Raman, and UV-Vis spectra of quinoline-7-carboxaldehyde.

    PubMed

    Kumru, M; Küçük, V; Kocademir, M; Alfanda, H M; Altun, A; Sarı, L

    2015-01-05

    Spectroscopic properties of quinoline-7-carboxaldehyde (Q7C) have been studied in detail both experimentally and theoretically. The FT-IR (4000-50 cm(-1)), FT-Raman (4000-50 cm(-1)), dispersive-Raman (3500-50 cm(-1)), and UV-Vis (200-400 nm) spectra of Q7C were recorded at room temperature (25 °C). Geometry parameters, potential energy surface about CCH(O) bond, harmonic vibrational frequencies, IR and Raman intensities, UV-Vis spectrum, and thermodynamic characteristics (at 298.15K) of Q7C were computed at Hartree-Fock (HF) and density functional B3LYP levels employing the 6-311++G(d,p) basis set. Frontier molecular orbitals, molecular electrostatic potential, and Mulliken charge analyses of Q7C have also been performed. Q7C has two stable conformers that are energetically very close to each other with slight preference to the conformer that has oxygen atom of the aldehyde away from the nitrogen atom of the quinoline.

  17. Solubilization of flurbiprofen within non-ionic Tween 20 surfactant micelles: a 19F and 1H NMR study.

    PubMed

    Saveyn, Pieter; Cocquyt, Ellen; Zhu, Wuxin; Sinnaeve, Davy; Haustraete, Katrien; Martins, José C; Van der Meeren, Paul

    2009-07-14

    The solubilization of the poorly water soluble anti-inflammatory drug flurbiprofen in non-ionic Tween 20 surfactant micellar solutions was studied by both (19)F and (1)H NMR spectroscopy in an acidic environment. These non-destructive techniques allowed us to investigate the effect of temperature cycling in situ. Using (19)F NMR, an increased solubilisation capacity was observed as the temperature increased. This effect became more pronounced above the cloud point, which was reduced by more than 30 degrees C in the presence of an excess of flurbiprofen. Upon clouding, peak splitting was observed in the (19)F spectrum, which indicates that two pools of solubilised flurbiprofen exist that are in slow exchange on the NMR frequency timescale. The clouding and solubilization processes were found to be reversible, albeit with slow kinetics. Based on chemical shift differences of both Tween 20 and flurbiprofen, as well as NOESY experiments, the flurbiprofen was found to be accumulated within the palisade layer of the Tween 20 micelles.

  18. Predicting paramagnetic 1H NMR chemical shifts and state-energy separations in spin-crossover host-guest systems.

    PubMed

    Isley, William C; Zarra, Salvatore; Carlson, Rebecca K; Bilbeisi, Rana A; Ronson, Tanya K; Nitschke, Jonathan R; Gagliardi, Laura; Cramer, Christopher J

    2014-06-14

    The behaviour of metal-organic cages upon guest encapsulation can be difficult to elucidate in solution. Paramagnetic metal centres introduce additional dispersion of signals that is useful for characterisation of host-guest complexes in solution using nuclear magnetic resonance (NMR). However, paramagnetic centres also complicate spectral assignment due to line broadening, signal integration error, and large changes in chemical shifts, which can be difficult to assign even for known compounds. Quantum chemical predictions can provide information that greatly facilitates the assignment of NMR signals and identification of species present. Here we explore how the prediction of paramagnetic NMR spectra may be used to gain insight into the spin crossover (SCO) properties of iron(II)-based metal organic coordination cages, specifically examining how the structure of the local metal coordination environment affects SCO. To represent the tetrahedral metal-organic cage, a model system is generated by considering an isolated metal-ion vertex: fac-ML3(2+) (M = Fe(II), Co(II); L = N-phenyl-2-pyridinaldimine). The sensitivity of the (1)H paramagnetic chemical shifts to local coordination environments is assessed and utilised to shed light on spin crossover behaviour in iron complexes. Our data indicate that expansion of the metal coordination sphere must precede any thermal SCO. An attempt to correlate experimental enthalpies of SCO with static properties of bound guests shows that no simple relationship exists, and that effects are likely due to nuanced dynamic response to encapsulation.

  19. Metabolic Discrimination of Catharanthus roseus Leaves Infected by Phytoplasma Using 1H-NMR Spectroscopy and Multivariate Data Analysis1

    PubMed Central

    Choi, Young Hae; Tapias, Elisabet Casas; Kim, Hye Kyong; Lefeber, Alfons W.M.; Erkelens, Cornelis; Verhoeven, Jacobus Th.J.; Brzin, Jernej; Zel, Jana; Verpoorte, Robert

    2004-01-01

    A comprehensive metabolomic profiling of Catharanthus roseus L. G. Don infected by 10 types of phytoplasmas was carried out using one-dimensional and two-dimensional NMR spectroscopy followed by principal component analysis (PCA), an unsupervised clustering method requiring no knowledge of the data set and used to reduce the dimensionality of multivariate data while preserving most of the variance within it. With a combination of these techniques, we were able to identify those metabolites that were present in different levels in phytoplasma-infected C. roseus leaves than in healthy ones. The infection by phytoplasma in C. roseus leaves causes an increase of metabolites related to the biosynthetic pathways of phenylpropanoids or terpenoid indole alkaloids: chlorogenic acid, loganic acid, secologanin, and vindoline. Furthermore, higher abundance of Glc, Glu, polyphenols, succinic acid, and Suc were detected in the phytoplasma-infected leaves. The PCA of the 1H-NMR signals of healthy and phytoplasma-infected C. roseus leaves shows that these metabolites are major discriminating factors to characterize the phytoplasma-infected C. roseus leaves from healthy ones. Based on the NMR and PCA analysis, it might be suggested that the biosynthetic pathway of terpenoid indole alkaloids, together with that of phenylpropanoids, is stimulated by the infection of phytoplasma. PMID:15286294

  20. Metabolic Study of Breast MCF-7 Tumor Spheroids after Gamma Irradiation by 1H NMR Spectroscopy and Microimaging

    PubMed Central

    Palma, Alessandra; Grande, Sveva; Luciani, Anna Maria; Mlynárik, Vladimír; Guidoni, Laura; Viti, Vincenza; Rosi, Antonella

    2016-01-01

    Multicellular tumor spheroids are an important model system to investigate the response of tumor cells to radio- and chemotherapy. They share more properties with the original tumor than cells cultured as 2D monolayers do, which helps distinguish the intrinsic properties of monolayer cells from those induced during cell aggregation in 3D spheroids. The paper investigates some metabolic aspects of small tumor spheroids of breast cancer and their originating MCF-7 cells, grown as monolayer, by means of high–resolution (HR) 1H NMR spectroscopy and MR microimaging before and after gamma irradiation. The spectra of spheroids were characterized by higher intensity of mobile lipids, mostly neutral lipids, and glutamine (Gln) signals with respect to their monolayer cells counterpart, mainly owing to the lower oxygen supply in spheroids. Morphological changes of small spheroids after gamma-ray irradiation, such as loss of their regular shape, were observed by MR microimaging. Lipid signal intensity increased after irradiation, as evidenced in both MR localized spectra of the single spheroid and in HR NMR spectra of spheroid suspensions. Furthermore, the intense Gln signal from spectra of irradiated spheroids remained unchanged, while the low Gln signal observed in monolayer cells increased after irradiation. Similar results were observed in cells grown in hypoxic conditions. The different behavior of Gln in 2D monolayers and in 3D spheroids supports the hypothesis that a lower oxygen supply induces both an upregulation of Gln synthetase and a downregulation of glutaminases with the consequent increase in Gln content, as already observed under hypoxic conditions. The data herein indicate that 1H NMR spectroscopy can be a useful tool for monitoring cell response to different constraints. The use of spheroid suspensions seems to be a feasible alternative to localized spectroscopy since similar effects were found after radiation treatment. PMID:27200293

  1. 1H NMR Metabolic Fingerprinting to Probe Temporal Postharvest Changes on Qualitative Attributes and Phytochemical Profile of Sweet Cherry Fruit

    PubMed Central

    Goulas, Vlasios; Minas, Ioannis S.; Kourdoulas, Panayiotis M.; Lazaridou, Athina; Molassiotis, Athanassios N.; Gerothanassis, Ioannis P.; Manganaris, George A.

    2015-01-01

    Sweet cherry fruits (Prunus avium cvs. ‘Canada Giant’, ‘Ferrovia’) were harvested at commercial maturity stage and analyzed at harvest and after maintenance at room temperature (storage at ∼20°C, shelf life) for 1, 2, 4, 6, and 8 days, respectively. Fruit were initially analyzed for respiration rate, qualitative attributes and textural properties: ‘Canada Giant’ fruit were characterized by higher weight losses and stem browning index, being more intense over the late stages of shelf life period; meanwhile ‘Ferrovia’ possessed appreciably better performance even after extended shelf life period. A gradual decrease of respiration rate was monitored in both cultivars, culminated after 8 days at 20°C. The sweet cherry fruit nutraceutical profile was monitored using an array of instrumental techniques (spectrophotometric assays, HPLC, 1H-NMR). Fruit antioxidant capacity was enhanced with the progress of shelf life period, concomitant with the increased levels of total anthocyanin and of phenolic compounds. ‘Ferrovia’ fruit presented higher contents of neochlorogenic acid and p-coumaroylquinic acid throughout the shelf life period. We further developed an 1H-NMR method that allows the study of primary and secondary metabolites in a single running, without previous separation and isolation procedures. Diagnostic peaks were located in the aliphatic region for sugars and organic acids, in the aromatic region for phenolic compounds and at 8.2–8.6 ppm for anthocyanins. This NMR-based methodology provides a unifying tool for quantitative and qualitative characterization of metabolite changes of sweet cherry fruits; it is also expected to be further exploited for monitoring temporal changes in other fleshy fruits. PMID:26617616

  2. Prognosis Biomarkers of Severe Sepsis and Septic Shock by 1H NMR Urine Metabolomics in the Intensive Care Unit.

    PubMed

    Garcia-Simon, Monica; Morales, Jose M; Modesto-Alapont, Vicente; Gonzalez-Marrachelli, Vannina; Vento-Rehues, Rosa; Jorda-Miñana, Angela; Blanquer-Olivas, Jose; Monleon, Daniel

    2015-01-01

    Early diagnosis and patient stratification may improve sepsis outcome by a timely start of the proper specific treatment. We aimed to identify metabolomic biomarkers of sepsis in urine by (1)H-NMR spectroscopy to assess the severity and to predict outcomes. Urine samples were collected from 64 patients with severe sepsis or septic shock in the ICU for a (1)H NMR spectra acquisition. A supervised analysis was performed on the processed spectra, and a predictive model for prognosis (30-days mortality/survival) of sepsis was constructed using partial least-squares discriminant analysis (PLS-DA). In addition, we compared the prediction power of metabolomics data respect the Sequential Organ Failure Assessment (SOFA) score. Supervised multivariate analysis afforded a good predictive model to distinguish the patient groups and detect specific metabolic patterns. Negative prognosis patients presented higher values of ethanol, glucose and hippurate, and on the contrary, lower levels of methionine, glutamine, arginine and phenylalanine. These metabolites could be part of a composite biopattern of the human metabolic response to sepsis shock and its mortality in ICU patients. The internal cross-validation showed robustness of the metabolic predictive model obtained and a better predictive ability in comparison with SOFA values. Our results indicate that NMR metabolic profiling might be helpful for determining the metabolomic phenotype of worst-prognosis septic patients in an early stage. A predictive model for the evolution of septic patients using these metabolites was able to classify cases with more sensitivity and specificity than the well-established organ dysfunction score SOFA.

  3. Prognosis Biomarkers of Severe Sepsis and Septic Shock by 1H NMR Urine Metabolomics in the Intensive Care Unit

    PubMed Central

    Modesto-Alapont, Vicente; Gonzalez-Marrachelli, Vannina; Vento-Rehues, Rosa; Jorda-Miñana, Angela; Blanquer-Olivas, Jose; Monleon, Daniel

    2015-01-01

    Early diagnosis and patient stratification may improve sepsis outcome by a timely start of the proper specific treatment. We aimed to identify metabolomic biomarkers of sepsis in urine by 1H-NMR spectroscopy to assess the severity and to predict outcomes. Urine samples were collected from 64 patients with severe sepsis or septic shock in the ICU for a 1H NMR spectra acquisition. A supervised analysis was performed on the processed spectra, and a predictive model for prognosis (30-days mortality/survival) of sepsis was constructed using partial least-squares discriminant analysis (PLS-DA). In addition, we compared the prediction power of metabolomics data respect the Sequential Organ Failure Assessment (SOFA) score. Supervised multivariate analysis afforded a good predictive model to distinguish the patient groups and detect specific metabolic patterns. Negative prognosis patients presented higher values of ethanol, glucose and hippurate, and on the contrary, lower levels of methionine, glutamine, arginine and phenylalanine. These metabolites could be part of a composite biopattern of the human metabolic response to sepsis shock and its mortality in ICU patients. The internal cross-validation showed robustness of the metabolic predictive model obtained and a better predictive ability in comparison with SOFA values. Our results indicate that NMR metabolic profiling might be helpful for determining the metabolomic phenotype of worst-prognosis septic patients in an early stage. A predictive model for the evolution of septic patients using these metabolites was able to classify cases with more sensitivity and specificity than the well-established organ dysfunction score SOFA. PMID:26565633

  4. Metabolic profiling studies on the toxicological effects of realgar in rats by {sup 1}H NMR spectroscopy

    SciTech Connect

    Wei Lai; Liao Peiqiu; Wu Huifeng; Li Xiaojing Pei Fengkui Li Weisheng; Wu Yijie

    2009-02-01

    The toxicological effects of realgar after intragastrical administration (1 g/kg body weight) were investigated over a 21 day period in male Wistar rats using metabonomic analysis of {sup 1}H NMR spectra of urine, serum and liver tissue aqueous extracts. Liver and kidney histopathology examination and serum clinical chemistry analyses were also performed. {sup 1}H NMR spectra and pattern recognition analyses from realgar treated animals showed increased excretion of urinary Kreb's cycle intermediates, increased levels of ketone bodies in urine and serum, and decreased levels of hepatic glucose and glycogen, as well as hypoglycemia and hyperlipoidemia, suggesting the perturbation of energy metabolism. Elevated levels of choline containing metabolites and betaine in serum and liver tissue aqueous extracts and increased serum creatine indicated altered transmethylation. Decreased urinary levels of trimethylamine-N-oxide, phenylacetylglycine and hippurate suggested the effects on the gut microflora environment by realgar. Signs of impairment of amino acid metabolism were supported by increased hepatic glutamate levels, increased methionine and decreased alanine levels in serum, and hypertaurinuria. The observed increase in glutathione in liver tissue aqueous extracts could be a biomarker of realgar induced oxidative injury. Serum clinical chemistry analyses showed increased levels of lactate dehydrogenase, aspartate aminotransferase, and alkaline phosphatase as well as increased levels of blood urea nitrogen and creatinine, indicating slight liver and kidney injury. The time-dependent biochemical variations induced by realgar were achieved using pattern recognition methods. This work illustrated the high reliability of NMR-based metabonomic approach on the study of the biochemical effects induced by traditional Chinese medicine.

  5. 1H NMR-based serum metabolomics reveals erythromycin-induced liver toxicity in albino Wistar rats

    PubMed Central

    Rawat, Atul; Dubey, Durgesh; Guleria, Anupam; Kumar, Umesh; Keshari, Amit K.; Chaturvedi, Swati; Prakash, Anand; Saha, Sudipta; Kumar, Dinesh

    2016-01-01

    Introduction: Erythromycin (ERY) is known to induce hepatic toxicity which mimics other liver diseases. Thus, ERY is often used to produce experimental models of drug-induced liver-toxicity. The serum metabolic profiles can be used to evaluate the liver-toxicity and to further improve the understanding of underlying mechanism. Objective: To establish the serum metabolic patterns of Erythromycin induced hepatotoxicity in albino wistar rats using 1H NMR based serum metabolomics. Experimental: Fourteen male rats were randomly divided into two groups (n = 7 in each group): control and ERY treated. After 28 days of intervention, the metabolic profiles of sera obtained from ERY and control groups were analyzed using high-resolution 1D 1H CPMG and diffusion-edited nuclear magnetic resonance (NMR) spectra. The histopathological and SEM examinations were employed to evaluate the liver toxicity in ERY treated group. Results: The serum metabolic profiles of control and ERY treated rats were compared using multivariate statistical analysis and the metabolic patterns specific to ERY-induced liver toxicity were established. The toxic response of ERY was characterized with: (a) increased serum levels of Glucose, glutamine, dimethylamine, malonate, choline, phosphocholine and phospholipids and (b) decreased levels of isoleucine, leucine, valine, alanine, glutamate, citrate, glycerol, lactate, threonine, circulating lipoproteins, N-acetyl glycoproteins, and poly-unsaturated lipids. These metabolic alterations were found to be associated with (a) decreased TCA cycle activity and enhanced fatty acid oxidation, (b) dysfunction of lipid and amino acid metabolism and (c) oxidative stress. Conclusion and Recommendations: Erythromycin is often used to produce experimental models of liver toxicity; therefore, the established NMR-based metabolic patterns will form the basis for future studies aiming to evaluate the efficacy of anti-hepatotoxic agents or the hepatotoxicity of new drug

  6. Metabolomics study of Saw palmetto extracts based on 1H NMR spectroscopy.

    PubMed

    de Combarieu, Eric; Martinelli, Ernesto Marco; Pace, Roberto; Sardone, Nicola

    2015-04-01

    Preparations containing Saw palmetto extracts are used in traditional medicine to treat benign prostatic hyperplasia. According to the European and the American Pharmacopoeias, the extract is obtained from comminuted Saw palmetto berries by a suitable extracting procedure using ethanol or supercritical carbon dioxide or a mixture of n-hexane and methylpentanes. In the present study an approach to metabolomics profiling using nuclear magnetic resonance (NMR) has been used as a finger-printing tool to assess the overall composition of the extracts. The phytochemical analysis coupled with principal component analysis (PCA) showed the same composition of the Saw palmetto extracts obtained with carbon dioxide and hexane with minor not significant differences for extracts obtained with ethanol. In fact these differences are anyhow lower than the batch-to-batch variability ascribable to the natural-occurring variability in the Saw palmetto fruits' phytochemical composition. The fingerprinting analysis combined with chemometric method, is a technique, which would provide a tool to comprehensively assess the quality control of Saw palmetto extracts.

  7. Harvest year effects on Apulian EVOOs evaluated by 1H NMR based metabolomics

    PubMed Central

    De Pascali, Sandra A.

    2016-01-01

    Nine hundred extra virgin olive oils (EVOO) were extracted from individual olive trees of four olive cultivars (Coratina, Cima di Mola, Ogliarola, Peranzana), originating from the provinces of Bari and Foggia (Apulia region, Southern Italy) and collected during two consecutive harvesting seasons (2013/14 and 2014/15). Following genetic identification of individual olive trees, a detailed Apulian EVOO NMR database was built using 900 oils samples obtained from 900 cultivar certified single trees. A study on the olive oil lipid profile was carried out by statistical multivariate analysis (Principal Component Analysis, PCA, Partial Least-Squares Discriminant Analysis, PLS-DA, Orthogonal Partial Least-Squares Discriminant Analysis, OPLS-DA). Influence of cultivar and weather conditions, such as the summer rainfall, on the oil metabolic profile have been evaluated. Mahalanobis distances and J2 criterion have been measured to assess the quality of resulting scores clusters for each cultivar in the two harvesting campaigns. The four studied cultivars showed non homogeneous behavior. Notwithstanding the geographical spread and the wide number of samples, Coratina showed a consistent behavior of its metabolic profile in the two considered harvests. Among the other three Peranzana showed the second more consistent behavior, while Cima di Mola and Ogliarola having the biggest change over the two years. PMID:27994965

  8. 1H NMR Metabolomics Study of Metastatic Melanoma in C57BL/6J Mouse Spleen

    PubMed Central

    Wang, Xuan; Hu, Mary; Feng, Ju; Liu, Maili; Hu, Jian Zhi

    2014-01-01

    Melanoma is a malignant tumor of melanocytes. Although extensive investigations have been done to study metabolic changes in primary melanoma in vivo and in vitro, little effort has been devoted to metabolic profiling of metastatic tumors in organs other than lymph nodes. In this work, NMR-based metabolomics combined with multivariate data analysis is used to study metastatic B16-F10 melanoma in C57BL/6J mouse spleen. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonal Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to find important metabolites responsible for discriminating the control and the melanoma groups. Two different strategies, i.e. spectral binning and spectral deconvolution, are used to reduce the original spectral data before statistical analysis. Spectral deconvolution is found to be superior for identifying a set of discriminatory metabolites between the control and the melanoma groups, especially when the sample size is small. OPLS results show that the melanoma group can be well separated from its control group. It is found that taurine, glutamate, aspartate, O-Phosphoethanolamine, niacinamide,ATP, lipids and glycerol derivatives are decreased statistically and significantly while alanine, malate, xanthine, histamine, dCTP, GTP, thymidine, 2′-Deoxyguanosine are statistically and significantly elevated. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in spleen. PMID:25383071

  9. Metabolomic Characterization of Nipple Aspirate Fluid by 1H NMR Spectroscopy and GC-MS

    PubMed Central

    Tredwell, Gregory D.; Miller, Jessica A.; Chow, H.-H. Sherry; Thompson, Patricia A.; Keun, Hector C.

    2015-01-01

    Nipple aspirate fluid (NAF) is a noninvasively obtained biofluid from the duct openings of the breast. NAF components are constantly secreted, metabolized, and reabsorbed by the epithelial lining of the lactiferous ducts of the breast. NAF has been studied as a potential breast tissue surrogate for the discovery of novel breast cancer risk, early detection, and treatment response biomarkers. We report the first unsupervised metabolite characterization of nipple aspirate fluid using NMR and GC-MS using convenience samples previously collected from four premenopausal and four postmenopausal women. A total of 38 metabolites were identified using the two analytical techniques, including amino acids, organic acids, fatty acids, and carbohydrates. Analytical reproducibility of metabolites in NAF by GC-MS was high across different extraction and analysis days. Overall, 31 metabolites had a coefficient of variation below 20%. By GC-MS, there were eight metabolites unique to NAF, 19 unique to plasma, and 24 shared metabolites. Correlative analysis of shared metabolites between matched NAF and plasma samples from pre- and postmenopausal women shows almost no correlations, with the exception being lactic acid, which was significantly negatively correlated (R2 = 0.57; P = 0.03). These results suggest that NAF is metabolically distinct from plasma and that the application of metabolomic strategies may be useful for future studies investigating breast cancer risk and intervention response biomarkers. PMID:24364541

  10. Complete (1)H and (13)C NMR chemical shift assignments of mono-, di-, and trisaccharides as basis for NMR chemical shift predictions of polysaccharides using the computer program casper.

    PubMed

    Roslund, Mattias U; Säwén, Elin; Landström, Jens; Rönnols, Jerk; Jonsson, K Hanna M; Lundborg, Magnus; Svensson, Mona V; Widmalm, Göran

    2011-08-16

    The computer program casper uses (1)H and (13)C NMR chemical shift data of mono- to trisaccharides for the prediction of chemical shifts of oligo- and polysaccharides. In order to improve the quality of these predictions the (1)H and (13)C, as well as (31)P when applicable, NMR chemical shifts of 30 mono-, di-, and trisaccharides were assigned. The reducing sugars gave two distinct sets of NMR resonances due to the α- and β-anomeric forms. In total 35 (1)H and (13)C NMR chemical shift data sets were obtained from the oligosaccharides. One- and two-dimensional NMR experiments were used for the chemical shift assignments and special techniques were employed in some cases such as 2D (1)H,(13)C-HSQC Hadamard Transform methodology which was acquired approximately 45 times faster than a regular t(1) incremented (1)H,(13)C-HSQC experiment and a 1D (1)H,(1)H-CSSF-TOCSY experiment which was able to distinguish spin-systems in which the target protons were only 3.3Hz apart. The (1)H NMR chemical shifts were subsequently refined using total line-shape analysis with the PERCH NMR software. The acquired NMR data were then utilized in the casper program (http://www.casper.organ.su.se/casper/) for NMR chemical shift predictions of the O-antigen polysaccharides from Klebsiella O5, Shigella flexneri serotype X, and Salmonella arizonae O62. The data were compared to experimental data of the polysaccharides from the two former strains and the lipopolysaccharide of the latter strain showing excellent agreement between predicted and experimental (1)H and (13)C NMR chemical shifts.

  11. Al coordination and water speciation in hydrous aluminosilicate glasses: direct evidence from high-resolution heteronuclear 1H-27Al correlation NMR.

    PubMed

    Xue, Xianyu; Kanzaki, Masami

    2007-02-01

    In order to shed light on the dissolution mechanisms of water in depolymerized aluminosilicate melts/glasses, a comprehensive one- (1D) and two-dimensional (2D) NMR study has been carried out on hydrous Ca- and Mg-aluminosilicate glasses of a haplobasaltic composition. The applied techniques include 1D 1H MAS NMR and 27Al-->1H cross-polarization (CP) MAS NMR, and 2D 1H NOESY and double-quantum (DQ) MAS NMR, 27Al triple-quantum (3Q) MAS NMR and 27Al-->1H heteronuclear correlation (HETCOR) and 3QMAS/HETCOR NMR. Ab initio calculations were also performed to place additional constraints on the 1H NMR characteristics of AlOH and Si(OH)Al groups. This study has revealed, for the first time, the presence of free OH (i.e. (Ca, Mg)OH), SiOH and AlOH species, in addition to molecular H2O, in hydrous glasses of a depolymerized aluminosilicate composition. The AlOH groups are mostly associated with four-coordinate Al, but some are associated with five- and six-coordinate Al.

  12. 1H and 13C NMR signal assignment of cucurbitacin derivatives from Citrullus colocynthis (L.) Schrader and Ecballium elaterium L. (Cucurbitaceae).

    PubMed

    Seger, Christoph; Sturm, Sonja; Mair, Maria-Elisabeth; Ellmerer, Ernst P; Stuppner, Hermann

    2005-06-01

    2D NMR-derived 1H and 13C NMR signal assignments of six structurally closely related cucurbitacin derivatives are presented. The investigated 2-O-beta-D-glucopyranosylcucurbitacins I, J, K, and L were obtained from Citrullus colocynthis (L.) Schrader whereas the aglyca cucurbitacin E and I were isolated from Ecballium elaterium L.

  13. Metabolic Profiling of Intact Arabidopsis thaliana Leaves during Circadian Cycle Using 1H High Resolution Magic Angle Spinning NMR

    PubMed Central

    van Schadewijk, R.; de Groot, H. J. M.; Alia, A.

    2016-01-01

    Arabidopsis thaliana is the most widely used model organism for research in plant biology. While significant advances in understanding plant growth and development have been made by focusing on the molecular genetics of Arabidopsis, extracting and understanding the functional framework of metabolism is challenging, both from a technical perspective due to losses and modification during extraction of metabolites from the leaves, and from the biological perspective, due to random variation obscuring how well the function is performed. The purpose of this work is to establish the in vivo metabolic profile directly from the Arabidopsis thaliana leaves without metabolite extraction, to reduce the complexity of the results by multivariate analysis, and to unravel the mitigation of cellular complexity by predominant functional periodicity. To achieve this, we use the circadian cycle that strongly influences metabolic and physiological processes and exerts control over the photosynthetic machinery. High resolution-magic angle spinning nuclear magnetic resonance (HR-MAS NMR) was applied to obtain the metabolic profile directly from intact Arabidopsis leaves. Combining one- and two-dimensional 1H HR-MAS NMR allowed the identification of several metabolites including sugars and amino acids in intact leaves. Multivariate analysis on HR-MAS NMR spectra of leaves throughout the circadian cycle revealed modules of primary metabolites with significant and consistent variations of their molecular components at different time points of the circadian cycle. Since robust photosynthetic performance in plants relies on the functional periodicity of the circadian rhythm, our results show that HR-MAS NMR promises to be an important non-invasive method that can be used for metabolomics of the Arabidopsis thaliana mutants with altered physiology and photosynthetic efficiency. PMID:27662620

  14. Investigation of network heterogeneities in filled, trimodal, highly functional PDMS networks by 1H Multiple Quantum NMR

    SciTech Connect

    Gjersing, E; Chinn, S; Maxwell, R S; Herberg, J; Eastwood, E; Bowen, D; Stephens, T

    2006-09-06

    The segmental order and dynamics of polymer network chains in a filled, tri-modal silicone network have been studied by static 1H Multiple Quantum (MQ) NMR methods to gain insight into the structure property relationships. The materials were synthesized with two different types of crosslinks, with functionalities of 4 and near 60. The network chains were composed of distributions of high, low, and medium molecular weight chains. Crosslinking was accomplished by standard acid catalyzed reactions. MQ NMR methods have detected domains with residual dipolar couplings (<{Omega}{sub d}>) of near 4 kRad/s and 1 kRad/s assigned to (a) the shorter polymer chains and chains near the multifunctional ({phi}=60) crosslinking sites and to (b) the longer polymer chains far from these sites. Three structural variables were systematically varied and the mechanical properties and distributions of residual dipolar couplings measured in order to gain insight in to the network structural motifs that contribute significantly to the composite properties. The partitioning of and the average values of the residual dipolar couplings for the two domains were observed to be dependent on formulation variable and provided increased insight into the mechanical properties of these materials which are unavailable from swelling and spin-echo methods. The results of this study suggest that the domains with high crosslink density contribute significantly to the high strain modulus, while the low crosslink density domains do not. This is in agreement with theories and experimental studies on silicone bimodal networks over the last 20 years. In-situ MQ-NMR of swollen sample suggests that the networks deform non-affinely, in agreement with theory. The NMR experiments shown here provide increased ability to characterize multimodal networks of typical engineering silicone materials and to gain significant insight into structure-property relationships.

  15. Investigation of network heterogeneities in filled, trimodal, highly functional PDMS networks by 1H Multiple Quantum NMR

    SciTech Connect

    Maxwell, R; Gjersing, E; Chinn, S; Giuliani, J; Herberg, J; Eastwood, E; Bowen, D; Stephens, T

    2007-03-20

    The segmental order and dynamics of polymer network chains in a filled, tri-modal silicone foam network have been studied by static 1H Multiple Quantum (MQ) NMR methods to gain insight into the structure property relationships. The foam materials were synthesized with two different types of crosslinks, with functionalities, {phi}, of 4 and near 60. The network chains were composed of distributions of high, low, and medium molecular weight chains. Crosslinking was accomplished by standard acid catalyzed reactions. MQ NMR methods have detected domains with residual dipolar couplings (<{Omega}{sub d}>) of near 4 kRad/s and 1 kRad/s assigned to (a) the shorter polymer chains and chains near the multifunctional (f=60) crosslinking sites and to (b) the longer polymer chains far from these sites. Three structural variables were systematically varied and the mechanical properties via compression and distributions of residual dipolar couplings measured in order to gain insight in to the network structural motifs that contribute significantly to the composite properties. The partitioning of and the average values of the residual dipolar couplings for the two domains were observed to be dependent on formulation variable and provided increased insight into the network structure of these materials which are unavailable from swelling and spin-echo methods. The results of this study suggest that the domains with high crosslink density contribute significantly to the high strain modulus, while the low crosslink density domains do not. This is in agreement with theories and experimental studies on silicone bimodal networks over the last 20 years. In-situ MQ-NMR of swollen sample suggests that the networks deform heterogeneously and non-affinely. The heterogeneity of the deformation process was observed to depend on the amount of the high functionality crosslinking site PMHS. The NMR experiments shown here provide increased ability to characterize multimodal networks of typical

  16. sup 1 H NMR study of renal trimethylamine responses to dehydration and acute volume loading in man

    SciTech Connect

    Avison, M.J.; Rothman, D.L.; Nixon, T.W.; Long, W.S.; Siegel, N.J. )

    1991-07-15

    The authors have used volume-localized {sup 1}H NMR spectroscopy to detect and measure changes in medullary trimethylamines (TMAs) in the human kidney in vivo. Localized water-suppressed {sup 1}H spectra were collected from a volume of interest located within the renal medulla by using a stimulated echo-based localization scheme. The principal resonances in the medullary {sup 1}H spectrum were residual water, lipid, and TMAs. The TMA line width was 7-15 Hz before filtering, and the signal-to-noise ratio was 40:1. In four normal volunteers, 15 hr of dehydration led to a significant increase in urine ismolality and decrease in body weight and an increase in medullary TMAs. A subsequent water load caused a transient water diuresis, a return to euvolemic body weight, and a significant reduction in medullary TMAs within 4 hr. These results suggest that TMAs may play an osmoregulatory role in the medulla of the normal human kidney.

  17. 1H NMR study of robustoxin, the lethal neurotoxin from the funnel web spider Atrax robustus.

    PubMed

    Temple, M D; Hinds, M G; Sheumack, D D; Howden, M E; Norton, R S

    1999-03-01

    Robustoxin, the lethal neurotoxin from the Sydney funnel web spider Atrax robustus, is a polypeptide of 42 residues cross-linked by four disulfide bonds. This paper describes the sequence-specific assignment of resonances in the 1H nuclear magnetic resonance spectrum of robustoxin in aqueous solution. Several broad backbone amide resonances were encountered in spectra recorded at 27 degrees C, making the assignments at that temperature incomplete. In spectra recorded at lower temperatures these amide resonances became sharper, but others that were sharp at 27 degrees C became broad, indicative of conformational averaging on the millisecond timescale for certain regions of the structure. Nevertheless, it was possible to establish that robustoxin contains a small, triple-stranded, antiparallel beta-sheet and several reverse turns, but no alpha-helix. These observations indicate that this toxin may adopt the inhibitor cystine knot structure found in polypeptides from a diverse range of species, including a number of spiders. Analysis of the pH dependence of the spectrum yielded pKa values for Tyr22 and Tyr25, one of the three carboxyl groups, and the Lys residues.

  18. Intrauterine fetal brain NMR spectroscopy: 1H and 31P studies in rats

    SciTech Connect

    Nakada, T.; Kwee, I.L.; Suzuki, N.; Houkin, K. )

    1989-11-01

    Fetal brain metabolism was investigated in utero noninvasively using multinuclear nuclear magnetic resonance spectroscopy in rats at two representative prenatal stages: early (17-18 days) and late (20-21 days) stages. Phosphorus-31 (31P) spectroscopy revealed that phosphocreatine is significantly lower in the early stage and increases to the level of early neonates by the late prenatal stage. Intracellular pH at the early stage was found to be strikingly high (7.52 +/- 0.21) and decreased to a level similar to that of neonates by the late stage (7.29 +/- 0.07). Phosphomonoester levels at both stages were similar to the values reported for early neonates. Water-suppressed proton (1H) spectroscopy demonstrated a distinctive in vivo fetal brain spectral pattern characterized by low levels of N-acetyl aspartate and high levels of taurine. High-resolution proton spectroscopy and homonuclear chemical-shift correlate spectroscopy of brain perchloric acid extracts confirmed these in vivo findings. In vitro 31P spectroscopy of acidified chloroform methanol extracts showed the characteristic membrane phospholipid profiles of fetal brain. The phosphatidylethanolamine (PE)-to-phosphatidylcholine (PC) ratio (PE/PC) did not show significant changes between the two stages at 0.40 +/- 0.11, a value similar to that of early neonates.

  19. Change of translational-rotational coupling in liquids revealed by field-cycling 1H NMR

    NASA Astrophysics Data System (ADS)

    Meier, R.; Schneider, E.; Rössler, E. A.

    2015-01-01

    Applying the field-cycling nuclear magnetic resonance technique, the frequency dependence of the 1H spin-lattice relaxation rate, R 1 ω = T1 - 1 ω , is measured for propylene glycol (PG) which is increasingly diluted with deuterated chloroform. A frequency range of 10 kHz-20 MHz and a broad temperature interval from 220 to about 100 K are covered. The results are compared to those of experiments, where glycerol and o-terphenyl are diluted with their deuterated counter-part. Reflecting intra- as well as intermolecular relaxation, the dispersion curves R 1 ω , x (x denotes mole fraction PG) allow to extract the rotational time constant τrot(T, x) and the self-diffusion coefficient D(T, x) in a single experiment. The Stokes-Einstein-Debye (SED) relation is tested in terms of the quantity D(T, x) τrot(T, x) which provides a measure of an effective hydrodynamic radius or equivalently of the spectral separation of the translational and the rotational relaxation contribution. In contrast to o-terphenyl, glycerol and PG show a spectral separation much larger than suggested by the SED relation. In the case of PG/chloroform mixtures, not only an acceleration of the PG dynamics is observed with increasing dilution but also the spectral separation of rotational and translational relaxation contributions continuously decreases. Finally, following a behavior similar to that of o-terphenyl already at about x = 0.6; i.e., while D(T, x) τrot(T, x) in the mixture is essentially temperature independent, it strongly increases with x signaling thus a change of translational-rotational coupling. This directly reflects the dissolution of the hydrogen-bond network and thus a change of solution structure.

  20. 1H NMR Metabolomics: A New Molecular Level Tool for Assessment of Organic Contaminant Bioavailability to Earthworms in Soil

    NASA Astrophysics Data System (ADS)

    McKelvie, J. R.; Wolfe, D. M.; Celejewski, M. A.; Simpson, A. J.; Simpson, M. J.

    2009-05-01

    At contaminated field sites, the complete removal of polycyclic aromatic hydrocarbons (PAHs) is rarely achieved since a portion of these compounds remain tightly bound to the soil matrix. The concentration of PAHs in soil typically decreases until a plateau is reached, at which point the remaining contaminant is considered non- bioavailable. Numerous soil extraction techniques, including cyclodextrin extraction, have been developed to estimate contaminant bioavailability. However, these are indirect methods that do not directly measure the response of organisms to chemical exposure in soil. Earthworm metabolomics offers a promising new way to directly evaluate the bioavailability and toxicity of contaminants in soil. Metabolomics involves the measurement of changes in small-molecule metabolites, including sugars and amino acids, in living organisms due to an external stress, such as contaminant exposure. The objective of this study was to compare cyclodextrin extraction of soil (a bioavailability proxy) and 1H NMR metabolomic analysis of aqueous earthworm tissue extracts as indicators of contaminant bioavailability. A 30 day laboratory experiment was conducted using phenanthrene-spiked sphagnum peat soil and the OECD recommended earthworm species for toxicity testing, Eisenia fetida. The initial phenanthrene concentration in the soil was 320 mg/kg. Rapid biodegradation of phenanthrene occurred and concentrations decreased to 16 mg/kg within 15 days. After 15 days, phenanthrene biodegradation slowed and cyclodextrin extraction of the soil suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of the 1H NMR spectra for E. fetida tissue extracts indicated that the metabolic profile of phenanthrene exposed earthworms differed from control earthworms throughout the 30 day experiment. This suggests that the residual phenanthrene remaining in the soil after 15 days continued to elicit a metabolic response, even though it was not

  1. Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation.

    PubMed

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Tohru; Tanaka, Kazuyuki; Kitamura, Satoshi; Takakura, Asako; Hayashi, Takashi; Muranushi, Noriyuki

    2007-08-01

    The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an

  2. Local Water Dynamics in Coacervated Polyelectrolytes Monitored Through Dynamic Nuclear Polarization-Enhanced 1H NMR

    PubMed Central

    Kausik, Ravinath; Srivastava, Aasheesh; Korevaar, Peter A.; Stucky, Galen; Waite, J. Herbert

    2009-01-01

    We present the first study of quantifying the diffusion coefficient of interfacial water on polyelectrolyte surfaces of systems fully dispersed in bulk water under ambient conditions. Such measurements were made possible through the implementation of a recently introduced Dynamic Nuclear Polarization (DNP) technique to selectively amplify the nuclear magnetic resonance (NMR) signal of hydration water that is interacting with specifically located spin labels on polyelectrolyte surfaces. The merit of this novel capability is demonstrated in this report through the measurement of solvent microvisosity on the surface of two types of oppositely charged polyelectrolytes, when freely dissolved versus when complexed to form a liquid-liquid colloidal phase called complex coacervates. These complex coacervates were formed through electrostatic complexation between the imidazole-based cationic homopolymer poly(N-vinylimidazole) (PVIm), and anionic polypeptide polyaspartate (PAsp) in the pH range of 4.5 – 6.0, under which conditions the coacervate droplets are highly fluidic yet densely packed with polyelectrolytes. We also investigated the rotational diffusion coefficients of the spin labels covalently bound to the polyelectrolyte chains for both PVIm and PAsp, showing a 5 fold change in the rotational correlation time as well as anisotropy parameter upon coacervation, which represents a surprisingly small decrease given the high polymer concentration inside the dense microdroplets. For both DNP and ESR experiments, the polymers were covalently tagged with stable nitroxide radical spin labels (∼1 wt %) to probe the local solvent and polymer segment dynamics. We found that the surface water diffusion coefficients near uncomplexed PVIm and PAsp at pH 8 differ, and are around D∼1.3×10−9 m2 / s. In contrast, inside the complex coacervate phase, the water diffusion coefficient in the immediate vicinity of either polyelectrolyte was D∼ 0.25×10−9 m2 / s, which is about

  3. Stereospecific assignment of 1H resonances through chemical shift calculation and their use in structure determination by NMR

    NASA Astrophysics Data System (ADS)

    Harvey, Timothy S.; van Gunsteren, Wilfred F.; Ikura, Mitsuhiko

    1995-04-01

    Understanding of the factors which influence proton chemical shifts in nuclear magnetic resonance (NMR) spectra of proteins has advanced steadily as the number of proteins, for which assignments in conjunction with high resolution structures have been obtained, has increased. Progress has been made in both the calculation of chemical shifts from given coordinates, both empirically for 1H (Williamson & Asakura J. Magn. Reson. (1991) 94, 557) and using ab initio approaches for calculation of 13C (De Dios et al. Science (1993) 260, 1491). Concomitantly Wishart et al. (J. Mol. Biol. (1992) 222, 311), using statistical methods have clarified the relationship between Hα chemical shift and regular secondary structure in proteins to a high degree of accuracy. We recently demonstrated the significant amount of structural information present in the Hα chemical shift through the use of chemical shift restrained molecular dynamics simulations (Harvey & van Gunsteren Techniques in Protein Chemistry IV (1993) 615, Academic Press). Here we apply a similar methodology to the stereospecific assignment of methylene and methyl proton resonances in proteins. Stereospecific assignment of such 1H resonances dramatically increases the degree of precision of ensembles of structures derived from NMR data. However, this is often a cumbersome process, requiring detailed analysis of large amounts of data. Furthermore, experimental considerations such as poor signal-to-noise ratios, spectral overlap and spin diffusion combine to make this process somewhat unreliable. We present calculations of the chemical shifts for the known structures of bovine pancreatic trypsin inhibitor (Mw 6.5 kDa) and the α-amylase inhibitor tendamistat (Mw 8 kDa), for which stereospecific assignments and high resolution structures from both NMR and crystallographic studies are available. The methods described are also applied to the ensemble of structures obtained for protein S (Mw 19 kDa) for both structure

  4. Electronic states and molecular dynamics of single-component molecular conductors [M (tmdt) 2] (M =Ni , Pt) studied by 13C and 1H NMR

    NASA Astrophysics Data System (ADS)

    Takagi, Rina; Miyagawa, Kazuya; Yoshimura, Masahide; Gangi, Hiro; Kanoda, Kazushi; Zhou, Biao; Idobata, Yuki; Kobayashi, Akiko

    2016-01-01

    The molecular conductors [M(tmdt) 2] (M =Ni , Pt) consisting of single molecular species are investigated with 13C NMR and 1H NMR. The temperature dependences of the 13C NMR shift and relaxation rate provide microscopic evidence for the metallic nature with appreciable electron correlations. Both compounds exhibit an anomalous frequency-dependent enhancement in the 1H nuclear spin-lattice relaxation rate in a wide temperature range. These observations signify the presence of extraordinary molecular motions with low energy excitations.

  5. Probing intermolecular interactions in a diethylcarbamazine citrate salt by fast MAS (1)H solid-state NMR spectroscopy and GIPAW calculations.

    PubMed

    Venâncio, Tiago; Oliveira, Lyege Magalhaes; Ellena, Javier; Boechat, Nubia; Brown, Steven P

    2017-03-02

    Fast magic-angle spinning (MAS) NMR is used to probe intermolecular interactions in a diethylcarbamazine salt, that is widely used as a treatment against adult worms of Wuchereria bancrofti which cause a common disease in tropical countries named filariasis. Specifically, a dihydrogen citrate salt that has improved thermal stability and solubility as compared to the free form is studied. One-dimensional (1)H, (13)C and (15)N and two-dimensional (1)H-(13)C and (14)N-(1)H heteronuclear correlation NMR experiments under moderate and fast MAS together with GIPAW (CASTEP) calculations enable the assignment of the (1)H, (13)C and (14)N/(15)N resonances. A two-dimensional (1)H-(1)H double-quantum (DQ) -single-quantum (SQ) MAS spectrum recorded with BaBa recoupling at 60kHz MAS identifies specific proton-proton proximities associated with citrate-citrate and citrate-diethylcarbamazine intermolecular interactions.

  6. Solution structure of Ln(III) complexes with macrocyclic ligands through theoretical evaluation of 1H NMR contact shifts.

    PubMed

    Rodríguez-Rodríguez, Aurora; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Botta, Mauro; Tripier, Raphaël; Platas-Iglesias, Carlos

    2012-12-17

    Herein, we present a new approach that combines DFT calculations and the analysis of Tb(III)-induced (1)H NMR shifts to quantitatively and accurately account for the contact contribution to the paramagnetic shift in Ln(III) complexes. Geometry optimizations of different Gd(III) complexes with macrocyclic ligands were carried out using the hybrid meta-GGA TPSSh functional and a 46 + 4f(7) effective core potential (ECP) for Gd. The complexes investigated include [Ln(Me-DODPA)](+) (H(2)Me-DODPA = 6,6'-((4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diyl)bis(methylene))dipicolinic acid, [Ln(DOTA)(H(2)O)](-) (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate), [Ln(DOTAM)(H(2)O)](3+) (DOTAM = 1,4,7,10- tetrakis[(carbamoyl)methyl]-1,4,7,10-tetraazacyclododecane), and related systems containing pyridyl units (Ln = Gd, Tb). Subsequent all-electron relativistic calculations based on the DKH2 approximation, or small-core ECP calculations, were used to compute the (1)H hyperfine coupling constants (HFCCs) at the ligand nuclei (A(iso) values). The calculated A(iso) values provided direct access to contact contributions to the (1)H NMR shifts of the corresponding Tb(III) complexes under the assumption that Gd and Tb complexes with a given ligand present similar HFCCs. These contact shifts were used to obtain the pseudocontact shifts, which encode structural information as they depend on the position of the nucleus with respect to the lanthanide ion. An excellent agreement was observed between the experimental and calculated pseudocontact shifts using the DFT-optimized geometries as structural models of the complexes in solution, which demonstrates that the computational approach used provides (i) good structural models for the complexes, (ii) accurate HFCCs at the ligand nuclei. The methodology presented in this work can be classified in the context of model-dependent methods, as it relies on the use of a specific molecular structure obtained from DFT

  7. Heteronuclear three-dimensional NMR spectroscopy. Natural abundance sup 13 C chemical shift editing of sup 1 H- sup 1 H COSY spectra

    SciTech Connect

    Fesik, S.W.; Gampe, R.T. Jr.; Zuiderweg, E.R.P. )

    1989-01-18

    It has been demonstrated that heteronuclear 3D NMR spectroscopy can be effectively applied to small molecules with {sup 13}C at natural abundance. A 78mM solution of the aminoglycoside, kanamycin A was used for this experiment. The heteronuclear 3D NMR spectroscopy is shown to be a useful method for resolving spectral overlap in all frequency domains. 10 refs., 2 figs.

  8. Evaluation of the effect of carvacrol on the Escherichia coli 555 metabolome by using 1H-NMR spectroscopy.

    PubMed

    Picone, Gianfranco; Laghi, Luca; Gardini, Fausto; Lanciotti, Rosalba; Siroli, Lorenzo; Capozzi, Francesco

    2013-12-15

    Cultures of Escherichia coli 555 were grown at four levels of carvacrol (0-2 mM) and the E. coli endo-metabolome was extracted and measured by (1)H NMR spectroscopy. The results show that glucose concentration is going up with concentration of carvacrol and so do formate until the highest concentration is reached, from which point it suddenly decreases. This is interpreted as if the bacteria are increasingly unable to further metabolize glucose and as if the bacteria increasingly shifts with higher levels of carvacrol toward sugar fermentation as carbon source, until the level of carvacrol reaches a level (2.00 mM), where the E. coli must give up. Additionally, the multivariate Principal Component Analysis suggests that the adaptation occurring at sub-lethal doses of carvacrol is different from that occurring at higher doses.

  9. Study of the formation of carbonyl compounds in edible oils and fats by 1H-NMR and FTIR

    NASA Astrophysics Data System (ADS)

    Moya Moreno, M. C. M.; Mendoza Olivares, D.; Amézquita López, F. J.; Peris Martínez, V.; Bosch Reig, F.

    1999-05-01

    Oils and fats start decomposing from the moment they are isolated from their natural environment. Heating accelerates oxidative rancidity and frying at high temperatures produces thermal degradation with the formation of decomposition products, such as aldehydes, ketones, free acids and hydroxilic compounds that in high levels can be harmful to human health. The decomposition products formed up to 300°C were determined by means of 1H-NMR spectroscopy and an FTIR spectroscopic method was developed for the quantification of carbonyl compounds generated during heating. The results show that there is a formation of carbonyl compounds starting at 150°C and when the sample was heated at 300°C for 40 min, the following contents (expressed as butyraldehyde mass fraction) were found: olive oil 10.5%, sunflower oil 11.3%, corn oil 3.0%, seeds oil (sunflower, safflower and canola seed) 6.6% and lard 3.5%.

  10. [Studies by means of 1H NMR spectroscopy of complex formation of aromatic biologically active compounds with antibiotic topotecan].

    PubMed

    Mosunov, A A; Kostiukov, V V; Evstigneev, M P

    2012-01-01

    The analysis of heteroassociation of antibiotic topotecan (TPT) with aromatic biologically active compounds (BAC): caffeine, mutagens ethidium bromide and proflavine, antibiotic daunomycin, vitamins flavin-mononucleotide and nicotinamide, has been carried out in the work using 1H NMR spectroscopy data. The equilibrium constants of heteroassociation and induced chemical shifts of the protons have been obtained in the complexes with BAC. It is found that the complex formation TPT-BAC has the nature of stacking of the chromophores, additionally stabilized in the case of proflavine by intermolecular hydrogen bond. Calculation of the basic components of the Gibbs free energy of the complexation reactions is carried out, and the factors which stabilize and destabilize the heterocomplexes of molecules are revealed.

  11. 13C-CPMAS and 1H-NMR study of the inclusion complexes of beta-cyclodextrin with carvacrol, thymol, and eugenol prepared in supercritical carbon dioxide.

    PubMed

    Locci, Emanuela; Lai, Simona; Piras, Alessandra; Marongiu, Bruno; Lai, Adolfo

    2004-09-01

    Beta-cyclodextrin (beta-CD) inclusion complexes with carvacrol (1), thymol (2), and eugenol (3) (components of essential oils of vegetable origin) were prepared by the supercritical CO2 technique, and their structural characterization was achieved by means of 1H-NMR in aqueous solution and 13C-CPMAS NMR in the solid state. Evidence of the formation of the inclusion complexes for all the examined systems was obtained by 1H-NMR in solution, while 2D-ROESY-NMR experiments were used to investigate the geometry of inclusion. In addition, the dynamics of these inclusion complexes in the kHz timescale was investigated by analysis of the 1H and 13C spin-lattice relaxation times in the rotating frame.

  12. Combining biochemical with (1)H NMR-based metabolomics approach unravels the antidiabetic activity of genipin and its possible mechanism.

    PubMed

    Shen, Xiao-Li; Liu, Huan; Xiang, Huan; Qin, Xue-Mei; Du, Guan-Hua; Tian, Jun-Sheng

    2016-09-10

    Diabetes mellitus is a typical heterogeneous metabolic disorder characterized by abnormal metabolism of carbohydrates, lipids and proteins. Genipin possesses a wide spectrum of biological activities including ameliorating effects on diabetes, but the definite mechanism of this effect remains unknown. To investigate the antidiabetic activities of genipin and explore the biochemical changes of serum endogenous metabolites on diabetic rats induced by alloxan, (1)H NMR spectroscopy coupled with multivariate data analysis was used to. All rats were randomly divided into six groups including negative control (NC) group, diabetic mellitus (DM) group, metformin hydrochloride group, high dose group of genipin, middle dose group of genipin and low dose group of genipin. Diabetes was induced by a single intraperitoneal injection of 120mg/kg body weight of alloxan. Serum samples were collected for the (1)H NMR-based metabolomics and clinical biochemical analysis. Daily oral administration of genipin (25, 50 and 100mg/kg body weight) and metformin hydrochloride (125mg/kg) for two weeks showed beneficial effects on blood glucose level (P<0.01). Significant differences in the metabolic profile as well as the result of biochemical parameters between the diabetic group and the control group were observed. The PLS-DA scores and corresponding loading plots demonstrated that genipin significantly restored the abnormal metabolic state. Detailed analysis of the altered metabolite levels indicated that genipin significantly ameliorated the disturbance in glucose metabolism, tricarboxylic acid cycle, lipid metabolism and amino acid metabolism. Genipin showed the best anti-diabetic effects at a dose of 100mg/kg in rats. This finding indicates that chemical and metabolomic approaches could be powerful tools for the investigation of the biochemical changes in pathological conditions or drug treatment.

  13. A 1H NMR study of a ternary peptide complex that mimics the interaction between troponin C and troponin I.

    PubMed Central

    Slupsky, C. M.; Shaw, G. S.; Campbell, A. P.; Sykes, B. D.

    1992-01-01

    The troponin I peptide N alpha-acetyl TnI (104-115) amide (TnIp) represents the minimum sequence necessary for inhibition of actomyosin ATPase activity of skeletal muscle (Talbot, J.A. & Hodges, R.S. 1981, J. Biol. Chem. 256, 2798-3802; Van Eyk, J.E. & Hodges, R.S., 1988, J. Biol. Chem. 263, 1726-1732; Van Eyk, J.E., Kay, C.M., & Hodges, R.S., 1991, Biochemistry 30, 9974-9981). In this study, we have used 1H NMR spectroscopy to compare the binding of this inhibitory TnI peptide to a synthetic peptide heterodimer representing site III and site IV of the C-terminal domain of troponin C (TnC) and to calcium-saturated skeletal TnC. The residues whose 1H NMR chemical shifts are perturbed upon TnIp binding are the same in both the site III/site IV heterodimer and TnC. These residues include F102, I104, F112, I113, I121, I149, D150, F151, and F154, which are all found in the C-terminal domain hydrophobic pocket and antiparallel beta-sheet region of the synthetic site III/site IV heterodimer and of TnC. Further, the affinity of TnIp binding to the heterodimer (Kd = 192 +/- 37 microM) was found to be similar to TnIp binding to TnC (48 +/- 18 microM [Campbell, A.P., Cachia, P.J., & Sykes, B.D., 1991, Biochem. Cell Biol. 69, 674-681]). The results indicate that binding of the inhibitory region of TnI is primarily to the C-terminal domain of TnC. The results also indicate how well the synthetic peptide heterodimer mimics the C-terminal domain of TnC in structure and functional interactions. PMID:1304891

  14. Quantitative Quantum Mechanical Spectral Analysis (qQMSA) of (1)H NMR spectra of complex mixtures and biofluids.

    PubMed

    Tiainen, Mika; Soininen, Pasi; Laatikainen, Reino

    2014-05-01

    The quantitative interpretation of (1)H NMR spectra of mixtures like the biofluids is a demanding task due to spectral complexity and overlap. Complications may arise also from water suppression, T2-editing, protein interactions, relaxation differences of the species, experimental artifacts and, furthermore, the spectra may contain unknown components and macromolecular background which cannot be easily separated from baseline. In this work, tools and strategies for quantitative Quantum Mechanical Spectral Analysis (qQMSA) of (1)H NMR spectra from complex mixtures were developed and systematically assessed. In the present approach, the signals of well-defined, stoichiometric components are described by a QM model, while the background is described by a multiterm baseline function and the unknown signals using optimizable and adjustable lines, regular multiplets or any spectral structures which can be composed from spectral lines. Any prior knowledge available from the spectrum can also be added to the model. Fitting strategies for weak and strongly overlapping spectral systems were developed and assessed using two basic model systems, the metabolite mixtures without and with macromolecular (serum) background. The analyses show that if the spectra are measured in high-throughput manner, the consistent absolute quantification demands some calibration to compensate the different response factors of the protons and compounds. On the other hand, the results show that also the T2-edited spectra can be measured so that they obey well the QM rules. In general, qQMSA exploits and interprets the spectral information in maximal way taking full advantage from the QM properties of the spectra and, at the same time, offers chemical confidence which means that individual components can be identified with high confidence on the basis of their accurate spectral parameters.

  15. Detection, identification and quantification by 1H NMR of adulterants in 150 herbal dietary supplements marketed for improving sexual performance.

    PubMed

    Gilard, Véronique; Balayssac, Stéphane; Tinaugus, Aurélie; Martins, Nathalie; Martino, Robert; Malet-Martino, Myriam

    2015-01-01

    One hundred and fifty dietary supplements (DS) marketed to increase sexual performance were analyzed. All these formulations were claimed to contain only natural compounds, plant extracts and/or vitamins. (1)H NMR spectroscopy was used for detecting the presence of adulterants and for their identification and quantification. Mass spectrometry was used as a complementary method for confirming the chemical structures. 61% of DS were adulterated with phosphodiesterase-5 inhibitors (PDE-5i) (27% with the PDE-5i medicines sildenafil, tadalafil and vardenafil, and 34% with their structurally modified analogues). Among them, 64% contained only one PDE-5i and 36% mixtures of two, three and even four. The amounts of PDE-5i medicines were higher than the maximum recommended dose in 25% of DS tainted with these drugs. Additional 5.5% DS included other drugs for the treatment of sexual dysfunction (yohimbine, flibanserin, phentolamine, dehydroepiandrosterone or testosterone). Some DS (2.5%) contained products (osthole, icariin) extracted from plants known to improve sexual performance. Only 31% of the samples could be considered as true herbal/natural products. A follow-up over time of several DS revealed that manufacturers make changes in the chemical composition of the formulations. Lack of quality or consistent manufacture (contamination possibly due to inadequate cleaning of the manufacturing chain, presence of impurities or degradation products, various compositions of a given DS with the same batch number, inadequate labelling) indicated poor manufacturing practices. In conclusion, this paper demonstrates the power of (1)H NMR spectroscopy as a first-line method for the detection of adulterated herbal/natural DS and the need for more effective quality control of purported herbal DS.

  16. I. The synthesis and characterization of annulated uranocenes. II. The variable temperature /sup 1/H NMR of uranocenes

    SciTech Connect

    Luke, W.D.

    1980-01-01

    A general synthetic route to alkyl annulated cyclooctatetraene dianions and the corresponding annulated uranocenes has been developed. Dideprotonation of bicyclooctatrienes, resulting from reaction of cyclooctatetraene dianion with l,n-dialkylbromides or methanesulfonates, affords alkyl annulated cyclooctatetraene dianions in moderate yields. Dicyclopenteno-, bisdimethylcyclopenteno- and dicyclohexenouranocene were prepared from the corresponding cyclooctatetraene dianions and UCl/sub 4/. The structures of dicyclobuteno- and dicyclopentenouranocene were elucidated by single crystal X-ray diffraction, and the effects of annulation on the uranocene skeleton are discussed. Attempted synthesis of benzocyclooctatetraene and a benzannulated uranocene is reported. The variable temperature /sup 1/H NMR spectrum of uranocene has been reinvestigated from -100 to 100/sup 0/C. The isotropic shift was found to be linear in T/sup -1/ with an extrapolated intercept of 0 at T/sup -1/ = 0. Variable temperature /sup 1/H NMR spectra, from -80 to 70/sup 0/C, of 17 substituted uranocenes are reported. The energy barrier to ring rotation in 1,1', 4,4'-tetra-t-butyl-uranocene was determined to be 8.24 +- 0.5 kcal/mole while the barrier in the corresponding 1,1', 3,3'-tetra-t-butylferrocene was determined to be 13.1 kcal/mole. Alkyl substitution is shown to have little effect on the electronic and magnetic properties of the uranocene skeleton, and thus alkyl substituted uranocenes are treated as having effective axial symmetry in analysis of the observed isotropic shifts. Using diannulated uranocenes as model systems an analysis of the contact and pseudocontact components of the observed isotropic shifts in uranocene and alkyl substituted uranocenes is presented.

  17. Synthesis, structure characterization and antimicrobial evaluation of 4-(substituted phenylazo)-3,5-diacetamido-1H-pyrazoles

    NASA Astrophysics Data System (ADS)

    Kinali-Demirci, Selin; Demirci, Serkan; Kurt, Mustafa

    2013-04-01

    The present article deals with the synthesis, spectral characterization and antimicrobial activity of phenylazo dyes. All of the synthesized phenylazo dyes were characterized using ATR-FTIR, FT-Raman, 1H NMR, 13C NMR, elemental analysis and mass spectroscopic techniques. Solvent effects on the UV-Vis absorption spectra of these phenylazo dyes were studied. Acid and base effects on the visible absorption maxima of the phenylazo dyes were also reported. The structural and spectroscopic analysis of the molecules were carried out using Density Functional Theory (DFT) employing the standard 6-31G(d) basis set, and the optimized geometries and calculated vibrational frequencies were evaluated via comparison with experimental values. The antimicrobial activity of 4-(substituted phenylazo)-3,5-diacetamido-1H-pyrazoles was reported against bacteria, including B. cereus (RSKK 863), S. aureus (ATCC 259231), M. luteus (NRRL B-4375), E. coli (ATCC 11230) and the yeast C. albicans (ATCC 10239).

  18. The use of UV-VIS-NIR reflectance spectroscopy to identify iron minerals

    NASA Astrophysics Data System (ADS)

    Szalai , Z.; Kiss, K.; Jakab, G.; Sipos, P.; Belucz, B.; Németh, T.

    2013-11-01

    Iron minerals - which behave as indicators in earthly and Martian environments - can be identified by UV-VIS-NIR reflectance spectroscopy. The aim of this study was to compare the spectra of various soils and sediments all of which contain iron minerals but developed under different environmental conditions. To identify the mineral of the sediments we used the first and second derivatives of the Kubelka-Munk transformed spectra. According to their iron mineral composition, the analysed samples can be divided into three distinct groups. Goethite refers to the hydromorphic conditions, hematite suffers from the long and intense weathering in leaching environment. In the case of steppe climatic conditions the weathering is so weak that the appearance of pedogenic iron minerals is improbable in these soils.

  19. Thermal edible oil evaluation by UV-Vis spectroscopy and chemometrics.

    PubMed

    Gonçalves, Rhayanna P; Março, Paulo H; Valderrama, Patrícia

    2014-11-15

    Edible oils such as colza, corn, sunflower, soybean and olive were analysed by UV-Vis spectroscopy and Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS). When vegetable oils were heated at high temperatures (frying), oxidation products were formed which were harmful to human health in addition to degrading the antioxidants present, and this study aimed to evaluate tocopherol (one antioxidant present in oils) and the behaviour of oxidation products in edible oils. The MCR-ALS results showed that the degradation started at 110°C and 85°C, respectively, for sunflower and colza oils, while tocopherol concentration decreased and oxidation products increased starting at 70°C in olive oil. In soybean and corn oils, tocopherol concentration started to decrease and oxidation products increased at 50°C. The results suggested that sunflower, colza and olive oils offered more resistance to increasing temperatures, while soybean and corn oils were less resistant.

  20. Design and development of multi functional confocal laser scanning microscope with UV / VIS laser source

    NASA Astrophysics Data System (ADS)

    Kanai, Yoshikazu; Kanzaki, Yousuke; Wakaki, Moriaki; Takeyama, Norihide

    2005-08-01

    A high resolution Confocal Laser Scanning Microscope (CLSM) with UV / VIS light sources was developed as the first step of multi-functional microscope. The optical system is designed to optimize for both UV and VIS wavelengths. An UV laser is used to achieve higher resolution, and a VIS is for multi functions. A new objective lens specialized for this application was designed and fabricated. Specification of the lens and the optical system is NA:0.95, EFL:2.5mm, WD:1.5mm, Resolution:160nm and achromatic for two wavelengths of UV 325.0nm / VIS 632.8nm. Several specimens were characterized to check the performance of the system. Some optical materials under study were measured for evaluation, and interesting results could be obtained. Multi-functional measurements are being planed as a next step. This system will help the research of nano-structures, photonic-crystals and biology.

  1. Defects in UV-vis-NIR reflectance spectra as method for forgery detections in writing documents

    NASA Astrophysics Data System (ADS)

    Somma, F.; Aloe, P.; Schirripa Spagnolo, G.

    2010-11-01

    Documents have taken up a very important place in our society. Frauds committed in connection with documents are not at all uncommon, and, in fact, represent a very large domain of the forensic science called "questioned documents". In the field of forensic examination of questioned documents, the legitimacy of an ink entry is often an essential question. A common type of forgery consists in materially altering an existing writing or adding a new writing. These changes can be characterized by means of optical spectroscopy. The aim of this work is to perform the UV-vis-NIR reflectance spectrophotometry to analyze a range of blue and black commercial ballpoint pens, in order to investigate the discriminating abilities of the different inks found on the same document.

  2. The UV-vis absorption spectrum of the flavonol quercetin in methanolic solution: A theoretical investigation.

    PubMed

    Andrade-Filho, T; Ribeiro, T C S; Del Nero, J

    2009-07-01

    The UV-vis absorption spectrum of the solvated quercetin molecule in methanol was investigated theoretically by means of an elegant type of QM/MM scheme better known as sequential Monte Carlo/quantum mechanics (S-MC/QM) methodology. A set of 125 uncorrelated Monte Carlo molecular liquid structures were properly selected through the autocorrelation function of the energy in order to be used in the quantum mechanical calculations. These molecular liquid structures were obtained by means of the radial and minimum distance distribution functions. A detailed account of the pattern of hydrogen bond structures obtained in this study is also available. The computed results obtained here were directly compared with the available experimental data in order to validate our theoretical model and through this comparison a very good conformity between theoretical and available experimental results was found.

  3. UV-vis absorption spectroscopy and multivariate analysis as a method to discriminate tequila.

    PubMed

    Barbosa-García, O; Ramos-Ortíz, G; Maldonado, J L; Pichardo-Molina, J L; Meneses-Nava, M A; Landgrave, J E A; Cervantes-Martínez, J

    2007-01-01

    Based on the UV-vis absorption spectra of commercially bottled tequilas, and with the aid of multivariate analysis, it is proved that different brands of white tequila can be identified from such spectra, and that 100% agave and mixed tequilas can be discriminated as well. Our study was done with 60 tequilas, 58 of them purchased at liquor stores in various Mexican cities, and two directly acquired from a distillery. All the tequilas were of the "white" type, that is, no aged spirits were considered. For the purposes of discrimination and quality control of tequilas, the spectroscopic method that we present here offers an attractive alternative to the traditional methods, like gas chromatography, which is expensive and time-consuming.

  4. UV-vis absorption spectroscopy and multivariate analysis as a method to discriminate tequila

    NASA Astrophysics Data System (ADS)

    Barbosa-García, O.; Ramos-Ortíz, G.; Maldonado, J. L.; Pichardo-Molina, J. L.; Meneses-Nava, M. A.; Landgrave, J. E. A.; Cervantes-Martínez, J.

    2007-01-01

    Based on the UV-vis absorption spectra of commercially bottled tequilas, and with the aid of multivariate analysis, it is proved that different brands of white tequila can be identified from such spectra, and that 100% agave and mixed tequilas can be discriminated as well. Our study was done with 60 tequilas, 58 of them purchased at liquor stores in various Mexican cities, and two directly acquired from a distillery. All the tequilas were of the "white" type, that is, no aged spirits were considered. For the purposes of discrimination and quality control of tequilas, the spectroscopic method that we present here offers an attractive alternative to the traditional methods, like gas chromatography, which is expensive and time-consuming.

  5. Design progress of the solar UV-Vis-IR telescope (SUVIT) aboard SOLAR-C

    NASA Astrophysics Data System (ADS)

    Katsukawa, Y.; Ichimoto, K.; Suematsu, Y.; Hara, H.; Kano, R.; Shimizu, T.; Matsuzaki, K.

    2013-09-01

    We present a design progress of the Solar UV-Vis-IR Telescope (SUVIT) aboard the next Japanese solar mission SOLAR-C. SUVIT has an aperture diameter of ~1.4 m for achieving spectro-polarimetric observations with spatial and temporal resolution exceeding the Hinode Solar Optical Telescope (SOT). We have studied structural and thermal designs of the optical telescope as well as the optical interface between the telescope and the focal plane instruments. The focal plane instruments are installed into two packages, filtergraph and spectrograph packages. The spectropolarimeter is the instrument dedicated to accurate polarimetry in the three spectrum windows at 525 nm, 854 nm, and 1083 nm for observing magnetic fields at both the photospheric and chromospheric layers. We made optical design of the spectrograph accommodating the conventional slit spectrograph and the integral field unit (IFU) for two-dimensional coverage. We are running feasibility study of the IFU using fiber arrays consisting of rectangular cores.

  6. Microreactors with integrated UV/Vis spectroscopic detection for online process analysis under segmented flow.

    PubMed

    Yue, Jun; Falke, Floris H; Schouten, Jaap C; Nijhuis, T Alexander

    2013-12-21

    Combining reaction and detection in multiphase microfluidic flow is becoming increasingly important for accelerating process development in microreactors. We report the coupling of UV/Vis spectroscopy with microreactors for online process analysis under segmented flow conditions. Two integration schemes are presented: one uses a cross-type flow-through cell subsequent to a capillary microreactor for detection in the transmission mode; the other uses embedded waveguides on a microfluidic chip for detection in the evanescent wave field. Model experiments reveal the capabilities of the integrated systems in real-time concentration measurements and segmented flow characterization. The application of such integration for process analysis during gold nanoparticle synthesis is demonstrated, showing its great potential in process monitoring in microreactors operated under segmented flow.

  7. Comparative study of the complex forming ability and enantioselectivity of cyclodextrin polymers by CE and 1H NMR.

    PubMed

    Danel, Cécile; Azaroual, Nathalie; Chavaria, Cédric; Odou, Pascal; Martel, Bernard; Vaccher, Claude

    2013-02-15

    The interactions between nine drugs (baclofen, bupivacaine, chlorpheniramine, ketoconazole, paliperidone, promethazine, propranolol, risperidone and verapamil) and six cyclodextrins (α-CD, β-CD, γ-CD, HP-β-CD, HP-γ-CD and Me-β-CD) or six polymers of cyclodextrins (polyα-CD, polyβ-CD, polyγ-CD, polyHP-β-CD, polyHP-γ-CD and polyMe-β-CD) were studied by affinity capillary electrophoresis and/or (1)H NMR at pH 2.5. An exhaustive qualitative study was performed through the determination of the retardation factor. Then, four compounds and both β-CD and polyβ-CD were selected for the quantitative study of the interactions at pH 2.5 and 7.0. By comparing the results obtained with the β-CD and polyβ-CD, it appears that the apparent binding constants are up to five times higher with the polymer. The 2D-NMR results seem to indicate that the structure of the polymeric network favours the inclusion of the guest in the hydrophobic cavity of the CD units. Moreover, the poly-CDs have shown very high enantioselective abilities at both pH.

  8. Tautomeric ratio and prototropic equilibrium constants of tenoxicam, a 1H and 13C NMR theoretical and experimental study.

    PubMed

    Franco-Pérez, Marco; Moya-Hernández, Rosario; Rojas-Hernández, Alberto; Gutiérrez, Atilano; Gómez-Balderas, Rodolfo

    2011-11-24

    The determination of the micro-equilibrium prototropic constants is often a tough task when the tautomeric ratio favors one of the species or when the chemical exchange is not slow enough to allow the quantitative detection of the tautomeric species. There are just few experimental methods available to reveal the constants of the tautomeric micro-equilibriums; its applicability depends on the nature of the tautomeric system. A combination of experimental and quantum chemistry calculated (1)H and (13)C NMR chemical shifts is presented here to estimate the population of the species participating in the tautomeric equilibriums of the tenoxicam, an important anti-inflammatory drug. A multivariate fitting of a fraction-mol-weighted contribution model, for the NMR chemical shifts of the species in solution, was used to find the populations of the tautomers of tenoxicam. To consider and evaluate the effect of the solvent polarity on the tautomers' populations, experimental determinations were carried out in DMSO-d(6), in an equimolar DMSO-H(2)O mixture of deuterated solvents and in D(2)O. Additionally, by employing HYPNMR, it has been possible to refine the acid-base macroscopic constants of tenoxicam.

  9. Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative (1)H NMR Metabonomic Study.

    PubMed

    Zafeiridis, Andreas; Chatziioannou, Anastasia Chrysovalantou; Sarivasiliou, Haralambos; Kyparos, Antonios; Nikolaidis, Michalis G; Vrabas, Ioannis S; Pechlivanis, Alexandros; Zoumpoulakis, Panagiotis; Baskakis, Constantinos; Dipla, Konstantina; Theodoridis, Georgios A

    2016-12-02

    The overall metabolic/energetic stress that occurs during an acute bout of exercise is proposed to be the main driving force for long-term training adaptations. Continuous and high-intensity interval exercise protocols (HIIE) are currently prescribed to acquire the muscular and metabolic benefits of aerobic training. We applied (1)H NMR-based metabonomics to compare the overall metabolic perturbation and activation of individual bioenergetic pathways of three popular aerobic exercises matched for effort/strain. Nine men performed continuous, long-interval (3 min), and short-interval (30 s) bouts of exercise under isoeffort conditions. Blood was collected before and after exercise. The multivariate PCA and OPLS-DA models showed a distinct separation of pre- and postexercise samples in three protocols. The two models did not discriminate the postexercise overall metabolic profiles of the three exercise types. Analysis focused on muscle bioenergetic pathways revealed an extensive upregulation of carbohydrate-lipid metabolism and the TCA cycle in all three protocols; there were only a few differences among protocols in the postexercise abundance of molecules when long-interval bouts were performed. In conclusion, continuous and HIIE exercise protocols, when performed with similar effort/strain, induce comparable global metabolic response/stress despite their marked differences in work-bout intensities. This study highlights the importance of NMR metabonomics in comprehensive monitoring of metabolic consequences of exercise training in the blood of athletes and exercising individuals.

  10. Benzocaine complexation with p-sulfonic acid calix[n]arene: experimental ((1) H-NMR) and theoretical approaches.

    PubMed

    Arantes, Lucas M; Varejão, Eduardo V V; Pelizzaro-Rocha, Karin J; Cereda, Cíntia M S; de Paula, Eneida; Lourenço, Maicon P; Duarte, Hélio A; Fernandes, Sergio A

    2014-05-01

    The aim of this work was to study the interaction between the local anesthetic benzocaine and p-sulfonic acid calix[n]arenes using NMR and theoretical calculations and to assess the effects of complexation on cytotoxicity of benzocaine. The architectures of the complexes were proposed according to (1) H NMR data (Job plot, binding constants, and ROESY) indicating details on the insertion of benzocaine in the cavity of the calix[n]arenes. The proposed inclusion compounds were optimized using the PM3 semiempirical method, and the electronic plus nuclear repulsion energy contributions were performed at the DFT level using the PBE exchange/correlation functional and the 6-311G(d) basis set. The remarkable agreement between experimental and theoretical approaches adds support to their use in the structural characterization of the inclusion complexes. In vitro cytotoxic tests showed that complexation intensifies the intrinsic toxicity of benzocaine, possibly by increasing the water solubility of the anesthetic and favoring its partitioning inside of biomembranes.

  11. Characterization of Chinese liquor starter, "Daqu", by flavor type with 1H NMR-based nontargeted analysis.

    PubMed

    Wu, Xiao-He; Zheng, Xiao-Wei; Han, Bei-Zhong; Vervoort, Jacques; Nout, M J Robert

    2009-12-09

    "Daqu" is a fermentation starter and substrate complex that is used to initiate fermentations for the production of Chinese liquor (alcoholic spirit). Several different types of Daqu are customary used, having different flavours, i.e. light, strong, or sauce flavor. With the aim to develop objective methods to characterize and distinguish such different types of Daqu, nontargeted analyses of extracts from three typical flavor types of Daqu were carried out using (1)H nuclear magnetic resonance (NMR) spectroscopy. A significant separation of spectra of Daqu of light-flavor, strong-flavor and sauce-flavor types was achieved using principal components analysis. The separation could be attributed to higher levels of glycerol, malate, acetate and N-acetylglutamine in light-flavor Daqu; higher levels of mannitol, betaine, trimethylamine and pyroglutamate in strong-flavor Daqu; and higher levels of lactate, isoleucine, leucine, isovalerate and valine in sauce-flavor Daqu. These metabolites were regarded as the representative metabolites or biomarkers characteristic for each type of Daqu and could be associated with some of the microorganisms that have been reported in Daqu. This study highlights the application of nontargeted analysis techniques based on NMR in process research and quality control in Daqu production and liquor fermentation.

  12. 1H NMR Spectroscopy and Multivariate Analysis of Monovarietal EVOOs as a Tool for Modulating Coratina-Based Blends

    PubMed Central

    Del Coco, Laura; De Pascali, Sandra Angelica; Fanizzi, Francesco Paolo

    2014-01-01

    Coratina cultivar-based olives are very common among 100% Italian extra virgin olive oils (EVOOs). Often, the very spicy character of this cultivar, mostly due to the high polyphenols concentration, requires blending with other “sweetener” oils. In this work, monovarietal EVOO samples from the Coratina cultivar (Apulia, Italy) were investigated and compared with monovarietal EVOO from native or recently introduced Apulian (Italy) cultivars (Ogliarola Garganica, Ogliarola Barese, Cima di Mola, Peranzana, Picholine), from Calabria (Italy) (Carolea and Rossanese) and from other Mediterranean countries, such as Spain (Picual) and Greece (Kalamata and Koroneiki) by 1H NMR spectroscopy and multivariate analysis (principal component analysis (PCA)). In this regard, NMR signals could allow a first qualitative evaluation of the chemical composition of EVOO and, in particular, of its minor component content (phenols and aldehydes), an intrinsic behavior of EVOO taste, related to the cultivar and geographical origins. Moreover, this study offers an opportunity to address blended EVOOs tastes by using oils from a specific region or country of origin. PMID:28234316

  13. (1)H NMR based metabolomics approach to study the toxic effects of herbicide butachlor on goldfish (Carassius auratus).

    PubMed

    Xu, Hua-Dong; Wang, Jun-Song; Li, Ming-Hui; Liu, Yan; Chen, Ting; Jia, Ai-Qun

    2015-02-01

    Butachlor, one of the most widely used herbicides in agriculture, has been reported with high ecotoxicity to aquatic plants and animals. In this study, a (1)H NMR based metabolomics approach combined with histopathological examination and biochemical assays was applied to comprehensively investigate the toxic effects of butachlor on four important organs (gill, brain, liver and kidney) of goldfish (Carassius auratus) for the first time. After 10 days' butachlor exposure at two dosages of 3.2 and 0.64 μmol/L, fish tissues (gill, brain, liver and kidney) and serum were collected. Histopathological inspection revealed severe impairment of gill filaments and obvious cellular edema in livers and kidneys. The increase of glutathione peroxidase (GSH-Px) activity in gill and methane dicarboxylic aldehyde (MDA) level in four tissues reflected the disturbance of antioxidative system in the intoxicated goldfish. Serum lactate dehydrogenase (LDH) activity and creatinine (CRE) level were increased in butachlor exposure groups, suggesting liver and kidney injuries induced by butachlor. Orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA) of NMR profiles disclosed metabolic changes that were related to the toxic effects of butachlor including oxidative stress, disorder of energy metabolism and amino acids metabolism, and disturbance of neurotransmitter balance in butachlor exposed goldfish. This integrated metabolomics approach provided a molecular basis underlying the toxicity of butachlor and demonstrated that metabolomics was a powerful and highly effective approach to elucidate the toxicity and underlying mechanisms of herbicides and pesticides, applicable for their risk assessment.

  14. Rapid milk group classification by 1H NMR analysis of Le and H epitopes in human milk oligosaccharide donor samples.

    PubMed

    van Leeuwen, Sander S; Schoemaker, Ruud J W; Gerwig, Gerrit J; van Leusen-van Kan, Ellen J M; Dijkhuizen, Lubbert; Kamerling, Johannis P

    2014-08-01

    Human milk oligosaccharides (HMOs) are a major constituent of human breast milk and play an important role in reducing the risk of infections in infants. The structures of these HMOs show similarities with blood group antigens in protein glycosylation, in particular in relation to fucosylation in Lewis blood group-type epitopes, matching the maternal pattern. Previously, based on the Secretor and Lewis blood group system, four milk groups have been defined, i.e. Lewis-positive Secretors, Lewis-positive non-Secretors, Lewis-negative Secretors and Lewis-negative non-Secretors. Here, a rapid one-dimensional (1)H nuclear magnetic resonance (NMR) analysis method is presented that identifies the presence/absence of (α1-2)-, (α1-3)- and (α1-4)-linked fucose residues in HMO samples, affording the essential information to attribute different HMO samples to a specific milk group. The developed method is based on the NMR structural-reporter-group concept earlier established for glycoprotein glycans. Further evaluation of the data obtained from the analysis of 36 HMO samples shows that within each of the four milk groups the relative levels of the different fucosylation epitopes can greatly vary. The data also allow a separation of the Lewis-positive Secretor milk group into two sub-groups.

  15. Water distribution in brine salted cod (Gadus morhua) and salmon (Salmo salar): a low-field 1H NMR study.

    PubMed

    Aursand, Ida G; Gallart-Jornet, Lorena; Erikson, Ulf; Axelson, David E; Rustad, Turid

    2008-08-13

    Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F

  16. (1)H-NMR-based metabolomic analysis of the effect of moderate wine consumption on subjects with cardiovascular risk factors.

    PubMed

    Vázquez-Fresno, Rosa; Llorach, Rafael; Alcaro, Francesca; Rodríguez, Miguel Ángel; Vinaixa, Maria; Chiva-Blanch, Gemma; Estruch, Ramon; Correig, Xavier; Andrés-Lacueva, Cristina

    2012-08-01

    Moderate wine consumption is associated with health-promoting activities. An H-NMR-based metabolomic approach was used to identify urinary metabolomic differences of moderate wine intake in the setting of a prospective, randomized, crossover, and controlled trial. Sixty-one male volunteers with high cardiovascular risk factors followed three dietary interventions (28 days): dealcoholized red wine (RWD) (272mL/day, polyphenol control), alcoholized red wine (RWA) (272mL/day) and gin (GIN) (100mL/day, alcohol control). After each period, 24-h urine samples were collected and analyzed by (1) H-NMR. According to the results of a one-way ANOVA, significant markers were grouped in four categories: alcohol-related markers (ethanol); gin-related markers; wine-related markers; and gut microbiota markers (hippurate and 4-hydroxphenylacetic acid). Wine metabolites were classified into two groups; first, metabolites of food metabolome: tartrate (RWA and RWD), ethanol, and mannitol (RWA); and second, biomarkers that relates to endogenous modifications after wine consumption, comprising branched-chain amino acid (BCAA) metabolite (3-methyl-oxovalerate). Additionally, a possible interaction between alcohol and gut-related biomarkers has been identified. To our knowledge, this is the first time that this approach has been applied in a nutritional intervention with red wine. The results show the capacity of this approach to obtain a comprehensive metabolome picture including food metabolome and endogenous biomarkers of moderate wine intake.

  17. Positional Enrichment by Proton Analysis (PEPA): A One-Dimensional (1) H-NMR Approach for (13) C Stable Isotope Tracer Studies in Metabolomics.

    PubMed

    Vinaixa, Maria; Rodríguez, Miguel A; Aivio, Suvi; Capellades, Jordi; Gómez, Josep; Canyellas, Nicolau; Stracker, Travis H; Yanes, Oscar

    2017-03-20

    A novel metabolomics approach for NMR-based stable isotope tracer studies called PEPA is presented, and its performance validated using human cancer cells. PEPA detects the position of carbon label in isotopically enriched metabolites and quantifies fractional enrichment by indirect determination of (13) C-satellite peaks using 1D-(1) H-NMR spectra. In comparison with (13) C-NMR, TOCSY and HSQC, PEPA improves sensitivity, accelerates the elucidation of (13) C positions in labeled metabolites and the quantification of the percentage of stable isotope enrichment. Altogether, PEPA provides a novel framework for extending the high-throughput of (1) H-NMR metabolic profiling to stable isotope tracing in metabolomics, facilitating and complementing the information derived from 2D-NMR experiments and expanding the range of isotopically enriched metabolites detected in cellular extracts.

  18. [Measurement of Water COD Based on UV-Vis Spectroscopy Technology].

    PubMed

    Wang, Xiao-ming; Zhang, Hai-liang; Luo, Wei; Liu, Xue-mei

    2016-01-01

    Ultraviolet/visible (UV/Vis) spectroscopy technology was used to measure water COD. A total of 135 water samples were collected from Zhejiang province. Raw spectra with 3 different pretreatment methods (Multiplicative Scatter Correction (MSC), Standard Normal Variate (SNV) and 1st Derivatives were compared to determine the optimal pretreatment method for analysis. Spectral variable selection is an important strategy in spectrum modeling analysis, because it tends to parsimonious data representation and can lead to multivariate models with better performance. In order to simply calibration models, the preprocessed spectra were then used to select sensitive wavelengths by competitive adaptive reweighted sampling (CARS), Random frog and Successive Genetic Algorithm (GA) methods. Different numbers of sensitive wavelengths were selected by different variable selection methods with SNV preprocessing method. Partial least squares (PLS) was used to build models with the full spectra, and Extreme Learning Machine (ELM) was applied to build models with the selected wavelength variables. The overall results showed that ELM model performed better than PLS model, and the ELM model with the selected wavelengths based on CARS obtained the best results with the determination coefficient (R2), RMSEP and RPD were 0.82, 14.48 and 2.34 for prediction set. The results indicated that it was feasible to use UV/Vis with characteristic wavelengths which were obtained by CARS variable selection method, combined with ELM calibration could apply for the rapid and accurate determination of COD in aquaculture water. Moreover, this study laid the foundation for further implementation of online analysis of aquaculture water and rapid determination of other water quality parameters.

  19. [Controllable synthesis and UV-Vis spectral analysis of silver nanoparticles in AOT microemulsion].

    PubMed

    Zhang, Wan-Zhong; Qiao, Xue-Liang; Luo, Lang-Li; Chen, Jian-Guo

    2009-03-01

    Colloidal silver nanoparticles were synthesized in water-in-oil microemulsion using silver nitrate solubilized in the water core of a microemulsion as source of silver ions, hydrazine hydrate solubilized in the water core of another one as reducing agent, cyclohexane as the continuous phase, and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as the surfactant. The main factors affecting the formation of silver nanoparticles were systematically studied. Ultraviolet-visible (UV-Vis) spectra were used for analyzing the effects of reaction parameters, including the type of reducing agents, the molar ratio of water to surfactant and the concentration of AgNO3 and AOT and so on, on the formation of silver nanoparticles. Original results for the controllable synthesis of silver nanoparticles were obtained when the synthesis proceeded in AOT-cyclohexane-AgNO3 microemulsion. The UV-Vis spectra of silver sols formed in the microemulsion with various parameters were studied systematically. The results show that the amount and average size of the obtained nanoparticles obviously depend on the above parameters. When the concentration of AgNO3 is lower, smaller silver nanoparticles are easy to form by increasing the concentration of AgNO3 appropriately. The higher W value was found to form larger numbers of silver nanoparticles with larger particle size. Compared to the solubility of NaBH4 in AOT reverse micelles, hydrazine hydrate is well soluble in these micelles, and thus it is favorable to reduce the silver ions solubilized in the water core of AOT-cyclohexane-AgNO3 microemulsion. The increase in the concentration of AOT induces an increase in the number of AOT micelles and a decrease in the molar ratio of water to surfactant. As a result, the solubilization capacity of reactants in the micelles increases and the radii of the micelles decrease. That is to say, with the increase in AOT concentration, the amount of the formed nanoparticles increases and the average size of the

  20. 1H and 13C NMR chemical shift assignments of spiro-cycloalkylidenehomo- and methanofullerenes by the DFT-GIAO method.

    PubMed

    Khalilov, L M; Tulyabaev, A R; Yanybin, V M; Tuktarov, A R

    2011-06-01

    The (1)H and (13)C NMR chemical shifts of spiro-cycloalkylidene[60]fullerenes were assigned using experimental NMR data and the Density Functional Theory (DFT)-Gauge Independence Of Atomic Orbitals method (GAIO) calculation method in the Perdew Burke Ernzerhof (PBE)/3z approach. The calculated values of the (13)C NMR chemical shifts adequately reproduce the experimental values at this quantum chemistry approach. Similar assignments will be helpful for (13)C NMR spectral analysis of homo- and methano[60]fullerene derivatives for structure elucidation and to determine the influence of fullerene frames on substituents and the influence of substituents on fullerene cores.

  1. Inverse nonionic microemulsion studied by means of 1H, 13C, and PGSTE NMR during silica nanoparticle synthesis.

    PubMed

    Asaro, Fioretta; Benedetti, Alvise; Savko, Nina; Pellizer, Giorgio

    2009-03-03

    The soluble species present in the reaction mixture that leads to silica nanoparticle production through the base catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) and the successive condensation were investigated in situ, under the actual synthesis conditions, by means of 1H, 13C, and 29Si NMR spectroscopy. The two former nuclei, owing to higher sensitivity and their presence both in the reacting species and in the constituents of the W/O microemulsion (cyclohexane-igepal-CA-520-concentrated ammonia solution) afforded insight into the inverse microemulsion and allowed us to assess the kinetic rate of the hydrolysis step. It was verified that the microemulsion microstructure is maintained during the reaction. The characterization of the final nanoparticles was carried out by means of transmission electron microscopy (TEM). Special attention was paid to the reaction medium, and an extended assignment of the 1H and 13C resonances of the surfactant headgroup is reported together with the discussion of the changes they undergo due to the environmental modifications induced by transition from cyclohexane solution to W/O microemulsion and further to NH3 containing W/O microemulsion. The self-diffusion coefficient measurements revealed that NH3 exchanges among the inverse micelles diffusing through cyclohexane and confirmed that the preferred localization for ethanol, a byproduct of the reaction, is the bulk oil.

  2. Dynamic structures of intact chicken erythrocyte chromatins as studied by 1H-31P cross-polarization NMR.

    PubMed Central

    Akutsu, H; Nishimoto, S; Kyogoku, Y

    1994-01-01

    The dynamic properties of DNA in intact chicken erythrocyte cells, nuclei, nondigested chromatins, digested soluble chromatins, H1, H5-depleted soluble chromatins and nucleosome cores were investigated by means of single-pulse and 1H-31P cross-polarization NMR. The temperature dependence of the phosphorus chemical shift anisotropy was identical for the former three in the presence of 3 mM MgCl2, suggesting that the local higher order structure is identical for these chromatins. The intrinsic phosphorus chemical shift anisotropy of the nucleosome cores was -159 ppm. The chemical shift anisotropy of DNA in the chromatins can be further averaged by the motion of the linker DNA. The spin-lattice relaxation time in the rotating frame of the proton spins (T1p) of the nondigested chromatins was measured at various locking fields. The result was analyzed on the assumption of the isotropic motion to get a rough value of the correlation time of the motion efficient for the relaxation, which was eventually ascribed to the segmental motion of the linker DNA with restricted amplitude. The 30 nm filament structure induced by NaCl was shown to be dynamically different from that induced by MgCl2. Side-by-side compaction of 30-nm filaments was suggested to be induced in the MgCl2 concentration range higher than 0.3 mM. Biological significance of the dynamic structure was discussed in connection with the results obtained. PMID:7948693

  3. The identification of vicinally substituted cyclohexane isomers in their mixtures by 1H and 13C NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Laihia, Katri; Kolehmainen, Erkki; Nevalainen, Tapio; Kauppinen, Reijo; Vasilieva, Tamara T.; Terentiev, Alexander B.

    2000-02-01

    The radical addition reactions of organobromine compounds, XBr (X=CH 2COOMe, PhCH 2, CHBr 2 and CCl 3) with cyclohexene afforded mixtures of cis/ trans isomer pairs of 1-X-2-Br-cyclohexanes. In addition to benzyl benzoyloxy derivatives are formed also, when benzoyl peroxide is used as an initiator. Owing to the great difficulties in separating these cis/ trans isomer pairs, they are identified directly in their mixtures by NMR spectroscopy. In addition to one-dimensional (1D) 1H, proton decoupled 13C and DEPT-135, also two-dimensional (2D) 13C- 13C INADEQUATE as well as 1H- 13C HMQC experiments have been used in assigning the signals of each compound in their mixtures. The identification of each isomer was based on comparison of experimental 3JH,H coupling constants with theoretical ones based on the well-known Karplus type relationship. The more stable conformation for each isomer was estimated using the semiempirical AM1 molecular orbital method. The calculations support the isomer pair elucidations.

  4. Stabilization of (CdSe)ZnS quantum dots with polypyrrole formed by UV/VIS irradiation initiated polymerization.

    PubMed

    Ramanavicius, A; Karabanovas, V; Ramanaviciene, A; Rotomskis, R

    2009-03-01

    Polypyrrole formation initiated by UV/VIS irradiation and stabilization of (CdSe)ZnS quantum dots is reported. Presented results demonstrate that UV/VIS irradiation is slowly destructing Q-dots that decreases quantum yield and shifts peak of photoluminescence (PL) spectra to short wavelength range. The same Q-dot solution under UV/VIS light irradiation in the presence of pyrrole is more stable, there is no PL band shifts only PL intensity of Q-dot decrease. UV/VIS induced Ppy formation process in the presence/absence of Q-dots dissolved in toluene and phosphate buffer saline (PBS) not containing Q-dots was investigated. The increase in the optical absorbance in the range of 400 nm-600 nm was exploited for the monitoring of polypyrrole formation process. Results obtained proved that in the presence of UV/VIS formed polypyrrole destruction of Q-dots is much slower if compared with bare Q-dots destruction under similar conditions. However, formed polypyrrole showed no positive effect on quantum yield of Q-dot, just the opposite-polypyrrole quenched Q-dot photoluminescence. Results presented and observation by other authors on pyrrole polymerization allow to predict that by UV/VIS induced polymerization formed polypyrrole is assembling polymeric layer on heterogeneous phase between Q-dot and toluene or water (in PBS solution). Established pi-pi conjugated chain of formed polypyrrole quenches photoluminescence of Q-dot because this polymer was formed in close proximity to Q-dot surface.

  5. Proton-detected 3D (15)N/(1)H/(1)H isotropic/anisotropic/isotropic chemical shift correlation solid-state NMR at 70kHz MAS.

    PubMed

    Pandey, Manoj Kumar; Yarava, Jayasubba Reddy; Zhang, Rongchun; Ramamoorthy, Ayyalusamy; Nishiyama, Yusuke

    2016-01-01

    Chemical shift anisotropy (CSA) tensors offer a wealth of information for structural and dynamics studies of a variety of chemical and biological systems. In particular, CSA of amide protons can provide piercing insights into hydrogen-bonding interactions that vary with the backbone conformation of a protein and dynamics. However, the narrow span of amide proton resonances makes it very difficult to measure (1)H CSAs of proteins even by using the recently proposed 2D (1)H/(1)H anisotropic/isotropic chemical shift (CSA/CS) correlation technique. Such difficulties due to overlapping proton resonances can in general be overcome by utilizing the broad span of isotropic chemical shifts of low-gamma nuclei like (15)N. In this context, we demonstrate a proton-detected 3D (15)N/(1)H/(1)H CS/CSA/CS correlation experiment at fast MAS frequency (70kHz) to measure (1)H CSA values of unresolved amide protons of N-acetyl-(15)N-l-valyl-(15)N-l-leucine (NAVL).

  6. The metabolism of 2-trifluormethylaniline and its acetanilide in the rat by 19F NMR monitored enzyme hydrolysis and 1H/19F HPLC-NMR spectroscopy.

    PubMed

    Tugnait, M; Lenz, E M; Hofmann, M; Spraul, M; Wilson, I D; Lindon, J C; Nicholson, J K

    2003-01-01

    The urinary excretion profile and identity of the metabolites of 2-trifluoromethyl aniline (2-TFMA) and 2-trifluoromethyl acetanilide (2-TFMAc), following i.p. administration to the rat at 50 mg kg(-1), were determined using a combination of 19F NMR monitored enzyme hydrolysis, SPEC-MS and 19F/1H HPLC-NMR. A total recovery of approximately 96.4% of the dose was excreted into the urine as seven metabolites. The major routes of metabolism were N-conjugation (glucuronidation), and ring-hydroxylation followed by sulphation (and to a lesser extent glucuronidation). The major metabolites excreted into the urine for both compounds were a labile N-conjugated metabolite (a postulated N-glucuronide) and a sulphated ring-hydroxylated metabolite (a postulated 4-amino-5-trifluoromethylphenyl sulphate) following dosing of 2-TFMA. These accounted for approximately 53.0 and 31.5% of the dose, respectively. This study identifies problems on sample component instability in the preparation and analysis procedures.

  7. The influence of membrane electrode assembly water content on the performance of a polymer electrolyte membrane fuel cell as investigated by 1H NMR microscopy.

    PubMed

    Feindel, Kirk W; Bergens, Steven H; Wasylishen, Roderick E

    2007-04-21

    The relation between the performance of a self-humidifying H(2)/O(2) polymer electrolyte membrane fuel cell and the amount and distribution of water as observed using (1)H NMR microscopy was investigated. The integrated (1)H NMR image signal intensity (proportional to water content) from the region of the polymer electrolyte membrane between the catalyst layers was found to correlate well with the power output of the fuel cell. Several examples are provided which demonstrate the sensitivity of the (1)H NMR image intensity to the operating conditions of the fuel cell. Changes in the O(2)(g) flow rate cause predictable trends in both the power density and the image intensity. Higher power densities, achieved by decreasing the resistance of the external circuit, were found to increase the water in the PEM. An observed plateau of both the power density and the integrated (1)H NMR image signal intensity from the membrane electrode assembly and subsequent decline of the power density is postulated to result from the accumulation of H(2)O(l) in the gas diffusion layer and cathode flow field. The potential of using (1)H NMR microscopy to obtain the absolute water content of the polymer electrolyte membrane is discussed and several recommendations for future research are provided.

  8. Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo (1)H NMR Spectroscopy.

    PubMed

    Nagana Gowda, G A; Abell, Lauren; Lee, Chi Fung; Tian, Rong; Raftery, Daniel

    2016-05-03

    Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple (1)H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD(+) and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD(+) ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD(+) and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD(+) and NADP(+) increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease.

  9. Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo 1H NMR Spectroscopy

    PubMed Central

    2016-01-01

    Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple 1H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD+ and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP+ and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD+ ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD+ and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD+ and NADP+ increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease. PMID:27043450

  10. Haemolymph from Mytilus galloprovincialis: Response to copper and temperature challenges studied by (1)H-NMR metabonomics.

    PubMed

    Digilio, Giuseppe; Sforzini, Susanna; Cassino, Claudio; Robotti, Elisa; Oliveri, Caterina; Marengo, Emilio; Musso, Davide; Osella, Domenico; Viarengo, Aldo

    2016-01-01

    Numerous studies on molluscs have been carried out to clarify the physiological roles of haemolymph serum proteins and haemocytes. However, little is known about the presence and functional role of the serum metabolites. In this study, Nuclear Magnetic Resonance (NMR) was used to assess whether changes of the metabolic profile of Mytilus galloprovincialis haemolymph may reflect alterations of the physiological status of the organisms due to environmental stressors, namely copper and temperature. Mussel haemolymph was taken from the posterior adductor muscle after a 4-day exposure to ambient (16 °C) or high temperature (24 °C) and in the absence or presence (5 μg/L, 20 μg/L, or 40 μg/L) of sublethal copper (Cu(2+)). The total glutathione (GSH) concentration in the haemolymph of both control and treated mussels was minimal, indicating the absence of significant contaminations by muscle intracellular metabolites due to the sampling procedure. In the (1)H-NMR spectrum of haemolymph, 27 metabolites were identified unambiguously. The separate and combined effects of exposure to copper and temperature on the haemolymph metabolic profile were assessed by Principal Component Analysis (PCA) and Ranking-PCA multivariate analysis. Changes of the metabolomic profile due to copper exposure at 16 °C became detectable at a dose of 20 μg/L copper. Alanine, lysine, serine, glutamine, glycogen, glucose and protein aliphatics played a major role in the classification of the metabolic changes according to the level of copper exposition. High temperature (24 °C) and high copper levels caused a coherent increase of a common set of metabolites (mostly glucose, serine, and lysine), indicating that the metabolic impairment due to high temperature is enforced by the presence of copper. Overall, the results demonstrate that, as for human blood plasma, the analysis of haemolymph metabolites represents a promising tool for the diagnosis of pollutant-induced stress syndrome in marine

  11. Detection of polyol accumulation in a new ovarian carcinoma cell line, CABA I: a1H NMR study

    PubMed Central

    Ferretti, A; D'Ascenzo, S; Knijn, A; Iorio, E; Dolo, V; Pavan, A; Podo, F

    2002-01-01

    Ovarian carcinomas represent a major form of gynaecological malignancies, whose treatment consists mainly of surgery and chemotherapy. Besides the difficulty of prognosis, therapy of ovarian carcinomas has reached scarce improvement, as a consequence of lack of efficacy and development of drug-resistance. The need of different biochemical and functional parameters has grown, in order to obtain a larger view on processes of biological and clinical significance. In this paper we report novel metabolic features detected in a series of different human ovary carcinoma lines, by 1H NMR spectroscopy of intact cells and their extracts. Most importantly, a new ovarian adenocarcinoma line CABA I, showed strong signals in the spectral region between 3.5 and 4.0 p.p.m., assigned for the first time to the polyol sorbitol (39±11 nmol/106 cells). 13C NMR analyses of these cells incubated with [1-13C]-D-glucose demonstrated labelled-sorbitol formation. The other ovarian carcinoma cell lines (OVCAR-3, IGROV 1, SK-OV-3 and OVCA432), showed, in the same spectral region, intense resonances from other metabolites: glutathione (up to 30 nmol/106 cells) and myo-inositol (up to 50 nmol/106 cells). Biochemical and biological functions are suggested for these compounds in human ovarian carcinoma cells, especially in relation to their possible role in cell detoxification mechanisms during tumour progression. British Journal of Cancer (2002) 86, 1180–1187. DOI: 10.1038/sj/bjc/6600189 www.bjcancer.com © 2002 Cancer Research UK PMID:11953869

  12. An approach to the simultaneous quantitative analysis of metabolites in table wines by (1)H NMR self-constructed three-dimensional spectra.

    PubMed

    Li, Bao Qiong; Xu, Min Li; Wang, Xue; Zhai, Hong Lin; Chen, Jing; Liu, Jin Jin

    2017-02-01

    Wine consists of several hundred components with different concentrations, including water, ethanol, glycerol, organic acids and sugars. Accurate quantification of target compounds in such complex samples is a difficult task based on conventional (1)H NMR spectra due to some challenges. In this paper, the three-dimensional spectrum was constructed firstly by simply repeating (1)H NMR spectrum itself so as to extract the features of target compounds by Tchebichef moment method. A proof-of-concept model system, the determination of five metabolites in wines was utilized to evaluate the performance of the proposed strategy. The results indicate that the proposed approach can provide accurate and reliable concentration predictions, probably the best results ever achieved using PLS and interval-PLS methods. Our novel strategy has not only good performance but also does not require laborious multi-step and subjective pretreatments. Therefore, it is expected that the proposed method could extend the application of conventional (1)H NMR.

  13. Selective Detection of 1H NMR Resonances of 13CH n Groups Using Two-Dimensional Maximum-Quantum Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, M.; Farrant, R. D.; Nicholson, J. K.; Lindon, J. C.

    Methods for editing spectra based upon maximum-quantum filtering in two-dimensional 1H NMR are presented (MAXY NMR). Separation of 1H resonances from 13CH, 13CH 2, and 13CH 3 groups is demonstrated, using the coherence of the attached natural-abundance 13C spin. Two-dimensional correlation pulse sequences based on J connectivity (MAXY-COSY), total J connectivity (MAXY-TOCSY), and NOE and exchange processes (MAXY-NOESY) are given and exemplified using dexamethasone as a model compound. In addition, an improved form of a 13CH 2 only COSY spectrum (gem-COSY) is shown, and the application of z magnetic-field gradients is demonstrated as an alternative to phase cycling. The approach should have utility in the assignment of complex 1H NMR spectra which arise from peptides or complex mixtures such as biofluids.

  14. Selective Detection of 1H NMR Resonances of CH n Groups Using a Heteronuclear Maximum-Quantum Filter and Pulsed Field Gradients

    NASA Astrophysics Data System (ADS)

    Liu, M.; Farrant, R. D.; Nicholson, J. K.; Lindon, J. C.

    A number of approaches are described for the provision of separate one-dimensional 1H NMR spectra of CH, CH 2, and CH 3 groups utilizing the natural-abundance 13C spins and based upon the selection of the maximum multiple-quantum coherences of the various groups, This sequence is termed edited maximum-quantum proton spectroscop y (MAXY) spectroscopy, The replacement of phase cycling with the application of z magnetic field gradient pulses is also demonstrated, The editing approach is demonstrated using the 1H NMR spectrum of dexamethasone in DMSO- d6 solution, Extension to a complex mixture biofluid is exemplified by the CH 3-only 1H NMR spectrum of human seminal plasma. This aid to the assignment of endogenous metabolite resonances is demonstrated to result in dramatic spectral simplification.

  15. Structure and equilibria of Ca 2+-complexes of glucose and sorbitol from multinuclear ( 1H, 13C and 43Ca) NMR measurements supplemented with molecular modelling calculations

    NASA Astrophysics Data System (ADS)

    Pallagi, A.; Dudás, Cs.; Csendes, Z.; Forgó, P.; Pálinkó, I.; Sipos, P.

    2011-05-01

    Ca 2+-complexation of D-glucose and D-sorbitol have been investigated with the aid of multinuclear ( 1H, 13C and 43Ca) NMR spectroscopy and ab initio quantum chemical calculations. Formation constants of the forming 1:1 complexes have been estimated from one-dimensional 13C NMR spectra obtained at constant ionic strength (1 M NaCl). Binding sites were identified from 2D 1H- 43Ca NMR spectra. 2D NMR measurements and ab initio calculations indicated that Ca 2+ ions were bound in a tridentate manner via the glycosidic OH, the ethereal oxygen in the ring and the OH on the terminal carbon for the α- and β-anomers of glucose and for sorbitol simultaneous binding of four hydroxide moieties (C1, C2, C4 and C6) was suggested.

  16. Screening enoxaparin tetrasaccharide SEC fractions for 3-O-sulfo-N-sulfoglucosamine residues using [(1)H,(15)N] HSQC NMR.

    PubMed

    Beecher, Consuelo N; Manighalam, Matthew S; Nwachuku, Adanma F; Larive, Cynthia K

    2016-02-01

    Heparin and heparan sulfate (HS) are important in mediating a variety of biological processes through binding to myriad different proteins. Specific structural elements along the polysaccharide chains are essential for high affinity protein binding, such as the 3-O-sulfated N-sulfoglucosamine (GlcNS3S) residue, a relatively rare modification essential for heparin's anticoagulant activity. The isolation of 3-O-sulfated oligosaccharides from complex mixtures is challenging because of their low abundance. Although methods such as affinity chromatography are useful in isolating oligosaccharides that bind specific proteins with high affinity, other important 3-O-sulfated oligosaccharides may easily be overlooked. Screening preparative-scale size-exclusion chromatography (SEC) fractions of heparin or HS digests using [(1)H,(15)N] HSQC NMR allows the identification of fractions containing 3-O-sulfated oligosaccharides through the unique (1)H and (15)N chemical shifts of the GlcNS3S residue. Those SEC fractions containing 3-O-sulfated oligosaccharides can then be isolated using strong anion-exchange (SAX)-HPLC. Compared with the results obtained by pooling the fractions comprising a given SEC peak, SAX-HPLC analysis of individual SEC fractions produces a less complicated chromatogram in which the 3-O-sulfated oligosaccharides are enriched relative to more abundant components. The utility of this approach is demonstrated for tetrasaccharide SEC fractions of the low molecular weight heparin drug enoxaparin facilitating the isolation and characterization of an unsaturated 3-O-sulfated tetrasaccharide containing a portion of the antithrombin-III binding sequence.

  17. UV-Vis spectroscopy of tyrosine side-groups in studies of protein structure. Part 2: selected applications.

    PubMed

    Antosiewicz, Jan M; Shugar, David

    In Part 2 we discuss application of several different types of UV-Vis spectroscopy, such as normal, difference, and second-derivative UV absorption spectroscopy, fluorescence spectroscopy, linear and circular dichroism spectroscopy, and Raman spectroscopy, of the side-chain of tyrosine residues in different molecular environments. We review the ways these spectroscopies can be used to probe complex protein structures.

  18. UV-Vis, infrared, and mass spectroscopy of electron irradiated frozen oxygen and carbon dioxide mixtures with water

    SciTech Connect

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-02-01

    Ozone has been detected on the surface of Ganymede via observation of the Hartley band through the use of ultraviolet spectroscopy and is largely agreed upon to be formed by radiolytic processing via interaction of magnetospheric energetic ions and/or electrons with oxygen-bearing ices on Ganymede's surface. Interestingly, a clearly distinct band near 300 nm within the shoulder of the UV-Vis spectrum of Ganymede was also observed, but currently lacks an acceptable physical or chemical explanation. Consequently, the primary motivation behind this work was the collection of UV-Vis absorption spectroscopy of ozone formation by energetic electron bombardment of a variety of oxygen-bearing ices (oxygen, carbon dioxide, water) relevant to this moon as well as other solar system. Ozone was indeed synthesized in pure ices of molecular oxygen, carbon dioxide and a mixture of water and oxygen, in agreement with previous studies. The Hartley band of the ozone synthesized in these ice mixtures was observed in the UV-Vis spectra and compared with the spectrum of Ganymede. In addition, a solid state ozone absorption cross section of 6.0 ± 0.6 × 10{sup –17} cm{sup 2} molecule{sup –1} was obtained from the UV-Vis spectral data. Ozone was not produced in the irradiated carbon dioxide-water mixtures; however, a spectrally 'red' UV continuum is observed and appears to reproduce well what is observed in a large number of icy moons such as Europa.

  19. DFT modeling, UV-Vis and IR spectroscopic study of acetylacetone-modified zirconia sol-gel materials.

    PubMed

    Georgieva, Ivelina; Danchova, Nina; Gutzov, Stoyan; Trendafilova, Natasha

    2012-06-01

    Theoretical and spectroscopic studies of a series of monomeric and dimeric complexes formed through the modification of a zirconium butoxide precursor with acetylacetone and subsequent hydrolysis and/or condensation have been performed by applying DFT/B3LYP/6-31++G(d) and highly accurate RI-ADC(2) methods as well as IR and UV-Vis transmittance and diffuse reflectance spectroscopies. Based on DFT model calculations and simulated and experimental UV-Vis and IR spectra of all the studied structures, the most probable building units of the Zr(IV)-AcAc gel were predicted: the dimeric double hydroxo-bridged complex Zr(2)(AcAc)(2)(OH)(4)(OH)(2br) 9 and the monooxo-bridged complex Zr(2)(AcAc)(2)(OH)(4)O(br)·2H(2)O 12. In both structures, the two AcAc ligands are coordinated to one Zr atom. It was shown that building units 9 and 12 determine the photophysical and vibrational properties of the gel material. The observed UV-Vis and IR spectra of Zr(IV)-AcAc gel were interpreted and a relation between the spectroscopic and structural data was derived. The observed UV-Vis bands at 315 nm and 298/288 nm were assigned to partial ligand-metal transitions and to intra-/inter-AcAc ligand transitions, respectively.

  20. Representativeness Errors in Comparing Chemistry Transport Models with Satellite UV/Vis Tropospheric Column Retrievals

    NASA Astrophysics Data System (ADS)

    Boersma, K. F.; Vinken, G. C.; Eskes, H.

    2015-12-01

    UV/Vis satellite retrievals of trace gas columns of nitrogen dioxide (NO2), sulphur dioxide (SO2), and formaldehyde (HCHO) are useful to test and improve models of atmospheric composition, for data assimilation, and to provide top-down constraints on emissions. However, because models and satellite measurements do not represent the exact same geophysical quantities, the process of confronting model fields with satellite measurements is complicated by representativeness errors, which degrade the quality of the comparison beyond contributions from modelling and measurement errors alone. Here we discuss representativeness errors that arise from the act of carrying out a model-satellite comparison: (1) horizontal representativeness errors due to imperfect collocation of the model grid cell and an ensemble of satellite pixels called superobservation, (2) temporal representativeness errors originating mostly from differences in cloud cover between the modelled and observed state, and (3) vertical representativeness errors because of reduced satellite sensitivity towards the surface. To minimize the impact of these representativeness errors, models and satellite measurements should be sampled as consistent as possible, and we provide recipes to do so. A practical confrontation of tropospheric NO2 columns simulated by the TM5 CTM with OMI tropospheric NO2 retrievals suggests that horizontal representativeness errors are <5-10% in most cases and of random nature. These errors should be included along with the individual retrieval errors in the overall superobservation error. Temporal sampling errors from mismatches in cloud cover, and in photolysis rates, are on the order of 10% for NO2 and HCHO, and systematic, but partly avoidable. In the case of air pollution applications where sensitivity down to the ground is required, models should be sampled on the same mostly cloud-free days as the satellite retrievals. The most relevant representativeness error is associated with

  1. Imazalil-cyclomaltoheptaose (beta-cyclodextrin) inclusion complex: preparation by supercritical carbon dioxide and 13C CPMAS and 1H NMR characterization.

    PubMed

    Lai, Simona; Locci, Emanuela; Piras, Alessandra; Porcedda, Silvia; Lai, Adolfo; Marongiu, Bruno

    2003-10-10

    An inclusion complex between imazalil (IMZ), a selected fungicide, and cyclomaltoheptaose (beta-cyclodextrin, betaCD) was obtained using supercritical fluid carbon dioxide. The best preparation conditions were determined, and the inclusion complex was investigated by means of 1H NMR spectroscopy in aqueous solution and 13C CPMAS NMR spectroscopy in the solid state. Information on the geometry of the betaCD/IMZ complex was obtained from ROESY spectroscopy, while the dynamics of the inclusion complex in the kilohertz range was obtained from the proton spin-lattice relaxation times in the rotating frame, T(1rho) (1H).

  2. A new salen base 5-(phenylazo)-N-(2-amino pyridine) salicyliden Schiff base ligand: synthesis, experimental and density functional studies on its crystal structure, FTIR, 1H NMR and 13C NMR spectra.

    PubMed

    Sheikhshoaie, Iran; Saheb, Vahid

    2010-12-01

    A novel Schiff base ligand 5-(phenylazo)-N-(2-amino pyridine) salicyliden is prepared through the condensation of 5-(phenylazo) salicylaldehyde and 2-amino pyridine in methanol at room temperature. The orange crystalline precipitate is used for X-ray crystallography and measuring Fourier transform (FTIR), 1H NMR and 13C NMR spectra. Density functional theory (DFT) calculations at the B3LYP, MPWB1K and B3PW91 levels of theory is used to optimize the geometry and calculate the FTIR, 1H NMR and 13C NMR spectra of the compound. The vibrational frequencies determined experimentally are compared with those obtained theoretically and a vibrational assignment and analysis of the fundamental modes of the compound is performed. We found that the MPWB1K method predicts low vibrational frequencies better than the commonly used B3LYP method. Although the B3PW91 method overestimates the 1H NMR chemical shifts, the values computed at the B3LYP level of theory are in accordance with experimental 1H NMR spectrum. However, both B3LYP and B3PW91 methods tend to overestimate 13C NMR chemical shifts. In addition, a few quantum descriptors of the molecule are calculated and conformational analysis is performed and the result was compared with crystallographic data.

  3. Detection of Butter Adulteration with Lard by Employing (1)H-NMR Spectroscopy and Multivariate Data Analysis.

    PubMed

    Fadzillah, Nurrulhidayah Ahmad; Man, Yaakob bin Che; Rohman, Abdul; Rosman, Arieff Salleh; Ismail, Amin; Mustafa, Shuhaimi; Khatib, Alfi

    2015-01-01

    The authentication of food products from the presence of non-allowed components for certain religion like lard is very important. In this study, we used proton Nuclear Magnetic Resonance ((1)H-NMR) spectroscopy for the analysis of butter adulterated with lard by simultaneously quantification of all proton bearing compounds, and consequently all relevant sample classes. Since the spectra obtained were too complex to be analyzed visually by the naked eyes, the classification of spectra was carried out.The multivariate calibration of partial least square (PLS) regression was used for modelling the relationship between actual value of lard and predicted value. The model yielded a highest regression coefficient (R(2)) of 0.998 and the lowest root mean square error calibration (RMSEC) of 0.0091% and root mean square error prediction (RMSEP) of 0.0090, respectively. Cross validation testing evaluates the predictive power of the model. PLS model was shown as good models as the intercept of R(2)Y and Q(2)Y were 0.0853 and -0.309, respectively.

  4. (1)H NMR-based DS determination of barley starch sulfates prepared in 1-allyl-3-methylimidazolium chloride.

    PubMed

    Kärkkäinen, Johanna; Wik, Tiia-Riikka; Niemelä, Matti; Lappalainen, Katja; Joensuu, Päivi; Lajunen, Marja

    2016-01-20

    The use of natural resources in a development of products and materials is currently increasing. Starch is one of the investigated resources due to its bioavailability, biodegradability, safety and affordability. In this study, native barley starch was sulfated using a SO3-pyridine complex. The reaction was carried out for the first time using 1-allyl-3-methylimidazolium chloride ionic liquid, an excellent solvent for the starch modification. Reaction conditions (temperature, time and amount of the reagent) were studied using an experimental design. Starch sulfates with the degree of substitution (DS) 1.37 were obtained when the reaction was carried out at 40 °C for 75 min with 4:1 molar ratio of SO3-pyridine complex:anhydroglucose unit. The determination of DS was based on (1)H NMR instead of elemental analysis, which showed overestimated DS values in this study. Starch sulfates were analyzed with FTIR and HPLC, which showed that products contained small and large sulfated molecules.

  5. 1H-NMR metabolic profiling of cerebrospinal fluid in patients with complex regional pain syndrome-related dystonia.

    PubMed

    Meissner, Axel; van der Plas, Anton A; van Dasselaar, Nick T; Deelder, André M; van Hilten, Jacobus J; Mayboroda, Oleg A

    2014-01-01

    In complex regional pain syndrome (CRPS)-related dystonia, compelling evidence points to the involvement of the central nervous system, but the underpinning pathobiology is still unclear. Thus, to enable a hypothesis-free, unbiased view of the problem and to obtain new insight into the pathobiology of dystonia in CRPS, we applied an exploratory metabolomics analysis of cerebrospinal fluid (CSF) of patients with CRPS-related dystonia. (1)H-NMR spectroscopy in combination with multivariate modeling were used to investigate metabolic profiles of a total of 105 CSF samples collected from patients with CRPS-related dystonia and controls. We found a significantly different metabolic profile of CSF in CRPS patients compared to controls. The differences were already reflected in the first two principal components of the principal component analysis model, which is an indication that the variance associated with CRPS is stronger than variance caused by such classical confounders as gender, age, or individual differences. A supervised analysis generated a strong model pinpointing the most important metabolites contributed to the metabolic signature of patients with CRPS-related dystonia. From the set of identified discriminators, the most relevant metabolites were 2-keto-isovalerate, glucose, glutamine, and lactate, which all showed increased concentrations, and urea, which showed decreased concentration in CRPS subjects. Our findings point at a catabolic state in chronic CRPS patients with dystonia that is likely associated with inflammation.

  6. 1H NMR study of the hetero-association of flavin-mononucleotide with mutagenic dyes: ethidium bromide and proflavine

    NASA Astrophysics Data System (ADS)

    Evstigneev, M. P.; Mukhina, Yu. V.; Davies, D. B.

    The hetero-association of the vitamin B2 derivative, flavin-mononucleotide (FMN), with a mutagenic dye, ethidium bromide (EB) or proflavine (PF), has been studied by 1D and 2D 500 MHz 1H NMR spectroscopy. The variations of proton chemical shifts of both the vitamin and dye as a function of concentration and temperature were analysed in terms of the structural and thermodynamical properties of the FMN-EB and FMN-PF complexes in solution. The structures of the complexes were also investigated by observed intermolecular ROE contacts and molecular mechanics calculations. The results show that the 1 : 1 hetero-association complexes in solution are more stable than the self-association complexes, which is consistent with formation of an intermolecular hydrogen-bond in the hetero-complexes of FMN-EB and FMN-PF. Hence it is possible that the toxicity of aromatic molecules such as EB and PF may be reduced in vitro by the presence of FMN, partly because of the known antimutagenic action of FMN and partly because it has been shown in this work that there is an effective intermolecular association between the mutagens and the vitamin.

  7. Optical, electrochemical, and 1H NMR characteristics of Mono-, Bi-, and tetranuclear cyclopalladated complexes with 4,4'-bipyridyl

    NASA Astrophysics Data System (ADS)

    Panova, A. G.; Puzyk, M. V.; Farus, O. A.; Balashev, K. P.

    2011-03-01

    The [Pd(C∧N)(4,4'-bpy)Cl], [Pd(C∧N)NO3]2(μ-4,4'-bpy) and [Pd(C∧N)(μ-4,4'-bpy)]4(NO3)4 complexes (C∧N- are deprotonated forms of 2-phenylpyridine (ppy), 2-(2''-thienyl)pyridine (tpy), and 2-phenylbenzothiazole (bt); bpy is 4,4' bipyridyl) are synthesized and characterized by 1H NMR spectroscopy, electronic absorption and emission spectroscopy, and cyclic voltammetry. The upfield shifts of the chemical shift of a proton in the ortho-position to the donor carbon atom of the cyclopalladated ligand of complexes (Δδ = -(1.1-1.5) ppm) is assigned to the anisotropic effect of the circular current of the pyridine rings of 4,4'-bipyridyl orthogonal to the coordination plane. The characteristic long-wavelength absorption and phosphorescence bands of the complexes are assigned to the chromophore metal-complex fragment {M(C∧N)}. The quasi-reversible reduction waves of complexes are assigned to the ligand-centered processes of successive electron transfer to the π*-orbitals localized mainly on the coordinated pyridine components of 4,4'-bipyridyl.

  8. Metastatic Melanoma Induced Metabolic Changes in C57BL/6J Mouse Stomach Measured by 1H NMR Spectroscopy

    DOE PAGES

    Hu, M; Wang, Xiliang

    2014-12-05

    Melanoma is a malignant tumor of melanocytes with high capability of invasion and rapid metastasis to other organs. Malignant melanoma is the most common metastatic malignancy found in gastrointestinal tract (GI). To the best of our knowledge, previous studies of melanoma in gastrointestinal tract are all clinical case reports. In this work, 1H NMR-based metabolomics approach is used to investigate the metabolite profiles differences of stomach tissue extracts of metastatic B16-F10 melanoma in C57BL/6J mouse and search for specific metabolite biomarker candidates. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonalmore » Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to evaluate important metabolites responsible for discriminating the control and the melanoma groups. Both PCA and OPLS results reveal that the melanoma group can be well separated from its control group. Among the 50 identified metabolites, it is found that the concentrations of 19 metabolites are statistically and significantly changed with the levels of O-phosphocholine and hypoxanthine down-regulated while the levels of isoleucine, leucine, valine, isobutyrate, threonine, cadaverine, alanine, glutamate, glutamine, methionine, citrate, asparagine, tryptophan, glycine, serine, uracil, and formate up-regulated in the melanoma group. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in stomach.« less

  9. Urinary (1)H-NMR and GC-MS metabolomics predicts early and late onset neonatal sepsis.

    PubMed

    Fanos, Vassilios; Caboni, Pierluigi; Corsello, Giovanni; Stronati, Mauro; Gazzolo, Diego; Noto, Antonio; Lussu, Milena; Dessì, Angelica; Giuffrè, Mario; Lacerenza, Serafina; Serraino, Francesca; Garofoli, Francesca; Serpero, Laura Domenica; Liori, Barbara; Carboni, Roberta; Atzori, Luigi

    2014-03-01

    The purpose of this article is to study one of the most significant causes of neonatal morbidity and mortality: neonatal sepsis. This pathology is due to a bacterial or fungal infection acquired during the perinatal period. Neonatal sepsis has been categorized into two groups: early onset if it occurs within 3-6 days and late onset after 4-7 days. Due to the not-specific clinical signs, along with the inaccuracy of available biomarkers, the diagnosis is still a major challenge. In this regard, the use of a combined approach based on both nuclear magnetic resonance ((1)H-NMR) and gas-chromatography-mass spectrometry (GC-MS) techniques, coupled with a multivariate statistical analysis, may help to uncover features of the disease that are still hidden. The objective of our study was to evaluate the capability of the metabolomics approach to identify a potential metabolic profile related to the neonatal septic condition. The study population included 25 neonates (15 males and 10 females): 9 (6 males and 3 females) patients had a diagnosis of sepsis and 16 were healthy controls (9 males and 7 females). This study showed a unique metabolic profile of the patients affected by sepsis compared to non-affected ones with a statistically significant difference between the two groups (p = 0.05).

  10. Metabolite Variation in Lean and Obese Streptozotocin (STZ)-Induced Diabetic Rats via (1)H NMR-Based Metabolomics Approach.

    PubMed

    Abu Bakar Sajak, Azliana; Mediani, Ahmed; Maulidiani; Ismail, Amin; Abas, Faridah

    2016-12-19

    Diabetes mellitus (DM) is considered as a complex metabolic disease because it affects the metabolism of glucose and other metabolites. Although many diabetes studies have been conducted in animal models throughout the years, the pathogenesis of this disease, especially between lean diabetes (ND + STZ) and obese diabetes (OB + STZ), is still not fully understood. In this study, the urine from ND + STZ, OB + STZ, lean/control (ND), and OB + STZ rats were collected and compared by using (1)H NMR metabolomics. The results from multivariate data analysis (MVDA) showed that the diabetic groups (ND + STZ and OB + STZ) have similarities and dissimilarities for a certain level of metabolites. Differences between ND + STZ and OB + STZ were particularly noticeable in the synthesis of ketone bodies, branched-chain amino acid (BCAA), and sensitivity towards the oral T2DM diabetes drug metformin. This finding suggests that the ND + STZ group was more similar to the T1DM model and OB + STZ to the T2DM model. In addition, we also managed to identify several pathways and metabolism aspects shared by obese (OB) and OB + STZ. The results from this study are useful in developing drug target-based research as they can increase understanding regarding the cause and effect of DM.

  11. (1)H NMR-Based Global Metabolic Studies of Pseudomonas aeruginosa upon Exposure of the Quorum Sensing Inhibitor Resveratrol.

    PubMed

    Chen, Tongtong; Sheng, Jiyang; Fu, Yonghong; Li, Minghui; Wang, Junsong; Jia, Ai-Qun

    2017-02-03

    Quorum sensing (QS) is a process of bacterial communication that has been a novel target for drug discovery. Pyocyanin quantification assay confirmed that resveratrol was an effective quorum sensing inhibitor (QSI) against Pseudomonas aeruginosa PAO1. In this study, the global metabolite changes of P. aeruginosa PAO1 exposed to QSI resveratrol were investigated by (1)H NMR spectroscopy. A total of 40 metabolites containing amino acids, organic acid, organic amine, and energy storage compounds were identified. The changed metabolic profile indicated that resveratrol influenced pathways including oxidative stress, protein synthesis, and energy metabolism. Oxidative stress could upregulate the expression of genes related to QS in P. aeruginosa. It suggested that resveratrol could inhibit the QS systems in P. aeruginosa PAO1 by relieving oxidative stress due to its antioxidant activity. On the other hand, resveratrol could attenuate the pathogenicity of P. aeruginosa PAO1 by disturbing the TCA cycle so that anaerobic respiration could suppress the virulence because anaerobiosis could induce the loss of cytotoxicity regulated by QS in P. aeruginosa. These findings deepened our comprehending of the metabolic responses of P. aeruginosa PAO1 to resveratrol and pinpointed the possible underlying mechanism of resveratrol's inhibition effect on QS in P. aeruginosa PAO1.

  12. Application of quantitative 1H-NMR method to determination of gentiopicroside in Gentianae radix and Gentianae scabrae radix.

    PubMed

    Tanaka, Rie; Hasebe, Yuko; Nagatsu, Akito

    2014-07-01

    A quantitative (1)H-NMR method (qHNMR) was used to measure gentiopicroside content in Gentianae radix and Gentianae scabrae radix. Gentiopicroside is a major component of Gentianae radix and Gentianae scabrae radix. The purity of gentiopicroside was calculated from the ratio of the intensity of the H-3 signal at δ 7.44 ppm or the H-8 signal at δ 5.78 ppm in methanol-d 4 of gentiopicroside to that of a hexamethyldisilane (HMD) signal at 0 ppm. The concentration of HMD was corrected with SI traceability by using potassium hydrogen phthalate of certified reference material (CRM) grade. As a result, the gentiopicroside content in two lots of Gentianae radix as determined by qHNMR was found to be 1.76 and 2.17 %, respectively. The gentiopicroside content in two lots of Gentianae scabrae radix was 2.73 and 3.99 %, respectively. We demonstrated that this method is useful for the quantitative analysis of crude drugs.

  13. Gender-Specific Metabolomic Profiling of Obesity in Leptin-Deficient ob/ob Mice by 1H NMR Spectroscopy

    PubMed Central

    Kim, Sang-Woo; Jung, Youngae; Bae, Hyun-Whee; Lee, Daeyoup; Park, Sung Goo; Lee, Chul-Ho; Hwang, Geum-Sook; Chi, Seung-Wook

    2013-01-01

    Despite the numerous metabolic studies on obesity, gender bias in obesity has rarely been investigated. Here, we report the metabolomic analysis of obesity by using leptin-deficient ob/ob mice based on the gender. Metabolomic analyses of urine and serum from ob/ob mice compared with those from C57BL/6J lean mice, based on the 1H NMR spectroscopy in combination with multivariate statistical analysis, revealed clear metabolic differences between obese and lean mice. We also identified 48 urine and 22 serum metabolites that were statistically significantly altered in obese mice compared to lean controls. These metabolites are involved in amino acid metabolism (leucine, alanine, ariginine, lysine, and methionine), tricarbocylic acid cycle and glucose metabolism (pyruvate, citrate, glycolate, acetoacetate, and acetone), lipid metabolism (cholesterol and carnitine), creatine metabolism (creatine and creatinine), and gut-microbiome-derived metabolism (choline, TMAO, hippurate, p-cresol, isobutyrate, 2-hydroxyisobutyrate, methylamine, and trigonelline). Notably, our metabolomic studies showed distinct gender variations. The obese male mice metabolism was specifically associated with insulin signaling, whereas the obese female mice metabolism was associated with lipid metabolism. Taken together, our study identifies the biomarker signature for obesity in ob/ob mice and provides biochemical insights into the metabolic alteration in obesity based on gender. PMID:24098417

  14. Metabolite signatures in hydrophilic extracts of mouse lungs exposed to cigarette smoke revealed by 1H NMR metabolomics investigation

    DOE PAGES

    Hu, Jian Z.; Wang, Xuan; Feng, Ju; ...

    2015-05-12

    Herein, 1H-NMR metabolomics are carried out to evaluate the changes of metabolites in lungs of mice exposed to cigarette smoke. It is found that the concentrations of adenosine derivatives (i.e. ATP, ADP and AMP), inosine and uridine are significantly fluctuated in the lungs of mice exposed to cigarette smoke compared with those of controls regardless the mouse is obese or regular weight. The decreased ATP, ADP, AMP and elevated inosine predict that the deaminases in charge of adenosine derivatives to inosine derivatives conversion are altered in lungs of mice exposed to cigarette smoke. Transcriptional analysis reveals that the concentrations ofmore » adenosine monophosphate deaminase and adenosine deaminase are different in the lungs of mice exposed to cigarette smoke, confirming the prediction from metabolomics studies. We also found, for the first time, that the ratio of glycerophosphocholine (GPC) to phosphocholine (PC) is significantly increased in the lungs of obese mice compared with regular weight mice. The ratio of GPC/PC is further elevated in the lungs of obese group by cigarette smoke exposure. Since GPC/PC ratio is a known biomarker for cancer, these results may suggest that obese group is more susceptible to lung cancer when exposed to cigarette smoke.« less

  15. Quantitative determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural in soluble coffees by 1H NMR spectrometry.

    PubMed

    del Campo, Gloria; Berregi, Iñaki; Caracena, Raúl; Zuriarrain, Juan

    2010-04-15

    A quantitative method for the determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural (5-HMF) in soluble coffees by applying the proton nuclear magnetic resonance technique ((1)H NMR) is proposed. Each of these compounds records a singlet signal at the 7.6-9.5 ppm interval of the spectrum, and its area is used to determine the concentration. 3-(Trimethylsilyl)-2,2,3,3-tetradeuteropropionic acid is added in an exact known concentration as a reference for delta=0.00 ppm and as an internal standard. The method is applied to commercial soluble coffees and satisfactorily compared with results obtained by standard methods. The limits of detection and the coefficients of variation (N=10) are, respectively, 1.32 mg/g of solid product and 4.2% for caffeine, 0.45 mg/g and 2.6% for formic acid, 0.58 mg/g and 2.4% for trigonelline, and 0.30 mg/g and 7.3% for 5-HMF. The described method is direct and no previous derivatization is needed.

  16. Interaction of phenylbutazone and colchicine in binding to serum albumin in rheumatoid therapy: 1H NMR study

    NASA Astrophysics Data System (ADS)

    Maciążek-Jurczyk, M.; Sułkowska, A.; Bojko, B.; Równicka-Zubik, J.; Sułkowski, W. W.

    2009-09-01

    The monitoring of drug concentration in blood serum is necessary in multi-drug therapy. Mechanism of drug binding with serum albumin (SA) is one of the most important factors which determine drug concentration and its transport to the destination tissues. In rheumatoid diseases drugs which can induce various adverse effects are commonly used in combination therapy. Such proceeding may result in the enhancement of those side effects due to drug interaction. Interaction of phenylbutazone and colchicine in binding to serum albumin and competition between them in gout has been studied by proton nuclear magnetic resonance ( 1H NMR) technique. The aim of the study was to determine the low affinity binding sites, the strength and kind of interaction between serum albumin and drugs used in combination therapy. The study of competition between phenylbutazone and colchicine in binding to serum albumin points to the change of their affinity to serum albumin in the ternary systems. This should be taken into account in multi-drug therapy. This work is a subsequent part of the spectroscopic study on Phe-COL-SA interactions [A. Sułkowska, et al., J. Mol. Struct. 881 (2008) 97-106].

  17. 1H NMR-based metabolic profiling reveals the effects of fluoxetine on lipid and amino acid metabolism in astrocytes.

    PubMed

    Bai, Shunjie; Zhou, Chanjuan; Cheng, Pengfei; Fu, Yuying; Fang, Liang; Huang, Wen; Yu, Jia; Shao, Weihua; Wang, Xinfa; Liu, Meiling; Zhou, Jingjing; Xie, Peng

    2015-04-15

    Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is a prescribed and effective antidepressant and generally used for the treatment of depression. Previous studies have revealed that the antidepressant mechanism of fluoxetine was related to astrocytes. However, the therapeutic mechanism underlying its mode of action in astrocytes remains largely unclear. In this study, primary astrocytes were exposed to 10 µM fluoxetine; 24 h post-treatment, a high-resolution proton nuclear magnetic resonance (1H NMR)-based metabolomic approach coupled with multivariate statistical analysis was used to characterize the metabolic variations of intracellular metabolites. The orthogonal partial least-squares discriminant analysis (OPLS-DA) score plots of the spectra demonstrated that the fluoxetine-treated astrocytes were significantly distinguished from the untreated controls. In total, 17 differential metabolites were identified to discriminate the two groups. These key metabolites were mainly involved in lipids, lipid metabolism-related molecules and amino acids. This is the first study to indicate that fluoxetine may exert antidepressant action by regulating the astrocyte's lipid and amino acid metabolism. These findings should aid our understanding of the biological mechanisms underlying fluoxetine therapy.

  18. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    PubMed

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained.

  19. Ion pairs of indobenzimidazolo cyanines: a structural study based on conductivity, absorption, fluorescence and 1H-NMR

    NASA Astrophysics Data System (ADS)

    Tatikolov, Aleksandr S.; Ishchenko, Aleksandr A.; Ghelli, Stefano; Ponterini, Glauco

    1998-11-01

    Asymmetric benzimidazolo carbo, di- and tricarbocyanines form ion pairs of the solvent-separated and contact types with different counterions in tetrahydrofuran, toluene and toluene-nitrile mixtures. The dissociation constants of the ion pairs in tetrahydrofuran, evaluated from conductivity data, do not depend on the length of the polymethine chain and show only a small decrease with decreasing counterion size. The absorption and fluorescence excitation spectra of the contact ion pairs exhibit a pronounced hypsochromic shift with respect to the solvated ions and the solvent-separated ion pairs. 1H-NMR experiments have provided information about the electronic structures of the ions of both the asymmetric dyes and the corresponding symmetric carbocyanines. They have also revealed different preferred anion locations in the contact ion pairs of the symmetric indocarbocyanine on one hand, and of the benzimidazolo carbocyanine and the asymmetric dyes on the other. This structural difference is suggested to be a cause of the observed opposite effects of ion pairing on the isomerization kinetics of the two groups of dyes.

  20. Metastatic Melanoma Induced Metabolic Changes in C57BL/6J Mouse Stomach Measured by 1H NMR Spectroscopy

    SciTech Connect

    Hu, M; Wang, Xiliang

    2014-12-05

    Melanoma is a malignant tumor of melanocytes with high capability of invasion and rapid metastasis to other organs. Malignant melanoma is the most common metastatic malignancy found in gastrointestinal tract (GI). To the best of our knowledge, previous studies of melanoma in gastrointestinal tract are all clinical case reports. In this work, 1H NMR-based metabolomics approach is used to investigate the metabolite profiles differences of stomach tissue extracts of metastatic B16-F10 melanoma in C57BL/6J mouse and search for specific metabolite biomarker candidates. Principal Component Analysis (PCA), an unsupervised multivariate data analysis method, is used to detect possible outliers, while Orthogonal Projection to Latent Structure (OPLS), a supervised multivariate data analysis method, is employed to evaluate important metabolites responsible for discriminating the control and the melanoma groups. Both PCA and OPLS results reveal that the melanoma group can be well separated from its control group. Among the 50 identified metabolites, it is found that the concentrations of 19 metabolites are statistically and significantly changed with the levels of O-phosphocholine and hypoxanthine down-regulated while the levels of isoleucine, leucine, valine, isobutyrate, threonine, cadaverine, alanine, glutamate, glutamine, methionine, citrate, asparagine, tryptophan, glycine, serine, uracil, and formate up-regulated in the melanoma group. These significantly changed metabolites are associated with multiple biological pathways and may be potential biomarkers for metastatic melanoma in stomach.

  1. LC-MS- and (1)H NMR-Based Metabolomic Analysis and in Vitro Toxicological Assessment of 43 Aristolochia Species.

    PubMed

    Michl, Johanna; Kite, Geoffrey C; Wanke, Stefan; Zierau, Oliver; Vollmer, Guenter; Neinhuis, Christoph; Simmonds, Monique S J; Heinrich, Michael

    2016-01-22

    Species of Aristolochia are used as herbal medicines worldwide. They cause aristolochic acid nephropathy (AAN), a devastating disease associated with kidney failure and renal cancer. Aristolochic acids I and II (1 and 2) are considered to be responsible for these nephrotoxic and carcinogenic effects. A wide range of other aristolochic acid analogues (AAAs) exist, and their implication in AAN may have been overlooked. An LC-MS- and (1)H NMR-based metabolomic analysis was carried out on 43 medicinally used Aristolochia species. The cytotoxicity and genotoxicity of 28 Aristolochia extracts were measured in human kidney (HK-2) cells. Compounds 1 and 2 were found to be the most common AAAs. However, AA IV (3), aristolactam I (4), and aristolactam BI (5) were also widespread. No correlation was found between the amounts of 1 or 2 and extract cytotoxicity against HK-2 cells. The genotoxicity and cytotoxicity of the extracts could be linked to their contents of 5, AA D (8), and AA IIIa (10). These results undermine the assumption that 1 and 2 are exclusively responsible for the toxicity of Aristolochia species. Other analogues are likely to contribute to their toxicity and need to be considered as nephrotoxic agents. These findings facilitate understanding of the nephrotoxic mechanisms of Aristolochia and have significance for the regulation of herbal medicines.

  2. Two-dimensional 1H-NMR study of the spatial structure of neurotoxin II from Naja naja oxiana.

    PubMed

    Golovanov, A P; Lomize, A L; Arseniev, A S; Utkin, Y N; Tsetlin, V I

    1993-05-01

    The spatial structure of neurotoxin II from the venom of the central Asian cobra Naja naja oxiana was determined by two-dimensional 1H-NMR techniques and computational analysis. Nearly complete proton resonance assignments for 61 amino acid residues have been made using two-dimensional (2D) homonuclear total correlated spectroscopy, 2D homonuclear double-quantum-filtered correlated spectroscopy and 2D homonuclear NOE spectroscopy (NOESY) experiments. The cross-peak volumes in NOESY spectra spin-spin coupling constants of vicinal protons NH-C alpha H and C alpha H-C beta H and the observation of slow deuterium exchange of amide protons were used to define local structure and a set of constraints for distance geometry program DIANA. The average root-mean-square deviations are 53 pm for backbone heavy atoms and 118 pm for all heavy atoms of 19 final neurotoxin II conformations. The spatial structure is characterized by a short double-stranded (residues 1-5 and 13-17) and a triple-stranded (residues 22-30, 33-41 and 50-54) antiparallel beta-sheets.

  3. Combined Transcriptomic–1H NMR Metabonomic Study Reveals That Monoethylhexyl Phthalate Stimulates Adipogenesis and Glyceroneogenesis in Human Adipocytes

    PubMed Central

    2011-01-01

    Adipose tissue is a major storage site for lipophilic environmental contaminants. The environmental metabolic disruptor hypothesis postulates that some pollutants can promote obesity or metabolic disorders by activating nuclear receptors involved in the control of energetic homeostasis. In this context, monoethylhexyl phthalate (MEHP) is of particular concern since it was shown to activate the peroxisome proliferator-activated receptor γ (PPARγ) in 3T3-L1 murine preadipocytes. In the present work, we used an untargeted, combined transcriptomic-1H NMR-based metabonomic approach to describe the overall effect of MEHP on primary cultures of human subcutaneous adipocytes differentiated in vitro. MEHP stimulated rapidly and selectively the expression of genes involved in glyceroneogenesis, enhanced the expression of the cytosolic phosphoenolpyruvate carboxykinase, and reduced fatty acid release. These results demonstrate that MEHP increased glyceroneogenesis and fatty acid reesterification in human adipocytes. A longer treatment with MEHP induced the expression of genes involved in triglycerides uptake, synthesis, and storage; decreased intracellular lactate, glutamine, and other amino acids; increased aspartate and NAD, and resulted in a global increase in triglycerides. Altogether, these results indicate that MEHP promoted the differentiation of human preadipocytes to adipocytes. These mechanisms might contribute to the suspected obesogenic effect of MEHP. PMID:22017230

  4. Geometry of the antitumor drug ditercalinium bisintercalated into d(CpGpCpG)2 by 1H NMR.

    PubMed Central

    Delbarre, A; Delepierre, M; Garbay, C; Igolen, J; Le Pecq, J B; Roques, B P

    1987-01-01

    Rigid 7H-pyrido[4,3-c]carbazole dimers, such as Ditercalinium, are DNA bisintercalators that display high DNA affinity and strong antitumor properties. This activity appears crucially dependent on the geometry of their complexes with DNA. Therefore, structures of the complexes formed by the self-complementary tetranucleotide d(CpGpCpG) with Ditercalinium and with a related monomer were investigated in 0.1 M [2H]acetate buffer (pH 5.5) by using 400-MHz 1H NMR. In both cases, d(CpGpCpG) retained a right-handed duplex structure as shown by exchangeable-proton analysis and intramolecular nuclear Overhauser effect measurements. According to the large upfield shifts measured on the base protons (including the imino proton) and on the aromatic protons of the pyridocarbazole rings, the monomer appears to monointercalate and the dimer to bisintercalate into the tetranucleotide duplex. Ditercalinium dissociates from its complex about 100-1000 times slower than does the monomer. The negative intermolecular nuclear Overhauser effects observed on protons corresponding to the convex edge of the pyridocarbazole rings when the sugar protons are saturated suggest that both ligands intercalate with their chain oriented to the wide groove side of the helix, a situation mimicking that encountered with repressors. Antitumor activity of 7H-pyridocarbazole derivatives is discussed in terms of geometry of the intercalated complexes. PMID:3470783

  5. Importance of Vibronic Effects in the UV-Vis Spectrum of the 7,7,8,8-Tetracyanoquinodimethane Anion.

    PubMed

    Tapavicza, Enrico; Furche, Filipp; Sundholm, Dage

    2016-10-11

    We present a computational method for simulating vibronic absorption spectra in the ultraviolet-visible (UV-vis) range and apply it to the 7,7,8,8-tetracyanoquinodimethane anion (TCNQ(-)), which has been used as a ligand in black absorbers. Gaussian broadening of vertical electronic excitation energies of TCNQ(-) from linear-response time-dependent density functional theory produces only one band, which is qualitatively incorrect. Thus, the harmonic vibrational modes of the two lowest doublet states were computed, and the vibronic UV-vis spectrum was simulated using the displaced harmonic oscillator approximation, the frequency-shifted harmonic oscillator approximation, and the full Duschinsky formalism. An efficient real-time generating function method was implemented to avoid the exponential complexity of conventional Franck-Condon approaches to vibronic spectra. The obtained UV-vis spectra for TCNQ(-) agree well with experiment; the Duschinsky rotation is found to have only a minor effect on the spectrum. Born-Oppenheimer molecular dynamics simulations combined with calculations of the electronic excitation energies for a large number of molecular structures were also used for simulating the UV-vis spectrum. The Born-Oppenheimer molecular dynamics simulations yield a broadening of the energetically lowest peak in the absorption spectrum, but additional vibrational bands present in the experimental and simulated quantum harmonic oscillator spectra are not observed in the molecular dynamics simulations. Our results underline the importance of vibronic effects for the UV-vis spectrum of TCNQ(-), and they establish an efficient method for obtaining vibronic spectra using a combination of linear-response time-dependent density functional theory and a real-time generating function approach.

  6. Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements.

    PubMed

    Sega, Alessandro; Zanardi, Iacopo; Chiasserini, Luisa; Gabbrielli, Alessandro; Bocci, Velio; Travagli, Valter

    2010-02-01

    Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives.

  7. Towards a NNORSY Ozone Profile ECV from European Nadir UV/VIS Measurements

    NASA Astrophysics Data System (ADS)

    Felder, Martin; Kaifel, Anton; Huckle, Roger

    2010-12-01

    The Neural Network Ozone Retrieval System (NNORSY) has been adapted and applied to several different satellite instruments, including the backscatter UV/VIS instruments ERS2-GOME, SCIAMACHY and METOP-GOME-2. The retrieved long term ozone field hence spans the years 1995 till now. To provide target data for training the neural networks, the lower parts of the atmosphere are sampled by ozone sondes from the WOUDC and SHADOZ data archives. Higher altitudes are covered by a variety of limb-sounding instruments, including the SAGE and POAM series, HALOE, ACE-FTS and AURA-MLS. In this paper, we show ozone profile time series over the entire time range to demonstrate the "out-of-the-box" consistency and homogeneity of our data across the three different nadir sounders, i.e. without any kind of tuning applied. These features of Essential Climate Variable (ECV) datasets [1] also lie at the heart of the recently announced ESA Climate Change Initiative, to which we hope to contribute in the near future.

  8. Capturing latent fingerprints from metallic painted surfaces using UV-VIS spectroscope

    NASA Astrophysics Data System (ADS)

    Makrushin, Andrey; Scheidat, Tobias; Vielhauer, Claus

    2015-03-01

    In digital crime scene forensics, contactless non-destructive detection and acquisition of latent fingerprints by means of optical devices such as a high-resolution digital camera, confocal microscope, or chromatic white-light sensor is the initial step prior to destructive chemical development. The applicability of an optical sensor to digitalize latent fingerprints primarily depends on reflection properties of a substrate. Metallic painted surfaces, for instance, pose a problem for conventional sensors which make use of visible light. Since metallic paint is a semi-transparent layer on top of the surface, visible light penetrates it and is reflected off of the metallic flakes randomly disposed in the paint. Fingerprint residues do not impede light beams making ridges invisible. Latent fingerprints can be revealed, however, using ultraviolet light which does not penetrate the paint. We apply a UV-VIS spectroscope that is capable of capturing images within the range from 163 to 844 nm using 2048 discrete levels. We empirically show that latent fingerprints left behind on metallic painted surfaces become clearly visible within the range from 205 to 385 nm. Our proposed streakiness score feature determining the proportion of a ridge-valley pattern in an image is applied for automatic assessment of a fingerprint's visibility and distinguishing between fingerprint and empty regions. The experiments are carried out with 100 fingerprint and 100 non-fingerprint samples.

  9. Analysis of organophosphate-Zn metalloporphyrin interactions via UV-vis spectroscopy and molecular modeling.

    PubMed

    Rompoti, A; Dalal, N; Athanasopoulos, D; Rutan, S; Helburn, R

    2015-01-25

    UV-vis absorption spectra of zinc tetraphenylporphine (ZnTPP) on interaction with six organophosphorus (OP) compounds in cyclohexane were compared using ab initio methods and the molecular and solvation ligand descriptors π(*), Vx, and σ. OPs with polarizable hydrocarbon substituents in the homologous series tri-ethyl, -pentyl, -octyl, and -phenyl phosphates and the toxicologically relevant methyl paraoxon (1a-e) each gave a red shift in the Soret band (λsor) of ZnTPP in the range of 8-10 nm. Sensitivity as ΔAsor-b/Δug OP for the spectral band of the ligand bound ZnTPP (λsor-b) decreased with increasing extent of alkyl and aromatic substitution. Calculated and combined energies for OP and ZnTPP examined as a function of distance (Å) between ligand and porphyrin center suggest increased steric crowding with increasing Vx, and aromatic content of the OP. Spectrally fitted K1:1 and ΔAsor-b/ug OP each vary exponentially with Vx/σ. Lack of a red shift in λsor-b where ZnTPP was titrated with the toxic diethyl chlorophosphate (1g) is consistent with a model in which the magnitude of ΔEsor is proportional to the donor capacity of the phosphoryl-O ligand.

  10. Quantitative characterization of the colloidal stability of metallic nanoparticles using UV-vis absorbance spectroscopy.

    PubMed

    Ray, Tyler R; Lettiere, Bethany; de Rutte, Joseph; Pennathur, Sumita

    2015-03-31

    Plasmonic nanoparticles are used in a wide variety of applications over a broad array of fields including medicine, energy, and environmental chemistry. The continued successful development of this material class requires the accurate characterization of nanoparticle stability for a variety of solution-based conditions. Although many characterization methods exists, there is an absence of a unified, quantitative means for assessing the colloidal stability of plasmonic nanoparticles. We present the particle instability parameter (PIP) as a robust, quantitative, and generalizable characterization technique based on UV-vis absorbance spectroscopy to characterize colloidal instability. We validate PIP performance with both traditional and alternative characterization methods by measuring gold nanorod instability in response to different salt (NaCl) concentrations. We further measure gold nanorod stability as a function of solution pH, salt, and buffer (type and concentration), nanoparticle concentration, and concentration of free surfactant. Finally, these results are contextualized within the literature on gold nanorod stability to establish a standardized methodology for colloidal instability assessment.

  11. Performance enhanced UV/vis spectroscopic microfluidic sensor for ascorbic acid quantification in human blood.

    PubMed

    Bi, Hongyan; Duarte, Carla M; Brito, Marina; Vilas-Boas, Vânia; Cardoso, Susana; Freitas, Paulo

    2016-11-15

    Quantitative analysis of antioxidants in a fast, simple and accurate manner is of great importance in the view of real-time monitoring the health of individuals. Recently, we have developed a UV/vis spectroscopic microfluidic sensor to specifically quantify ascorbic acid based on the immobilization of ascorbate oxidase, a relatively unstable enzyme. In this work, three different strategies for the immobilization of the unstable enzyme, including alumina sol-gel encapsulation, physisorption to PDMS channels with, and without alumina xerogel modification, were compared to build a microsensor. We found that the loading amount of the enzyme is not the determinative factor for the performance of the microfluidic biosensor but the retained activity of the enzyme and diffusion in the microfluidic channel. Taking into account of the two factors, the protocol of adsorbing enzymes to alumina (Al2O3) xerogel modified PDMS surface was demonstrated to be the best for preparing the microfluidic sensor among the utilized protocols. The microsensor prepared under the optimized protocol was further used to quantify ascorbic acid in human blood, where only dozens of microliters of blood (few drops) was required, demonstrating its potential application in clinical diagnosis. The developed strategy is featured with optimized enzymatic activity, simple process of microfluidic platform, low sample consumption, and straightforward spectrophotometry based detection.

  12. UV-Vis spectroscopy and solvatochromism of the tyrosine kinase inhibitor AG-1478.

    PubMed

    Khattab, Muhammad; Wang, Feng; Clayton, Andrew H A

    2016-07-05

    The effect of twenty-one solvents on the UV-Vis spectrum of the tyrosine kinase inhibitor AG-1478 was investigated. The absorption spectrum in the range 300-360nm consisted of two partially overlapping bands at approximately 340nm and 330nm. The higher energy absorption band was more sensitive to solvent and exhibited a peak position that varied from 327nm to 336nm, while the lower energy absorption band demonstrated a change in peak position from 340nm to 346nm in non-chlorinated solvents. The fluorescence spectrum of AG-1478 was particularly sensitive to solvent. The wavelength of peak intensity varied from 409nm to 495nm with the corresponding Stokes shift in the range of 64nm to 155nm (4536cm(-1) to 9210cm(-1)). We used a number of methods to assess the relationship between spectroscopic properties and solvent properties. The detailed analysis revealed that for aprotic solvents, the peak position of the emission spectrum in wavenumber scale correlated with the polarity (dielectric constant or ET(30)) of the solvent. In protic solvents, a better correlation was observed between the hydrogen bonding power of the solvent and the position of the emission spectrum. Moreover, the fluorescence quantum yields were larger in aprotic solvents as compared to protic solvents. This analysis underscores the importance of polarity and hydrogen-bonding environment on the spectroscopic properties of AG-1478. These studies will assume relevance in understanding the interaction of AG-1478 in vitro and in vivo.

  13. Broadband UV-Vis vibrational coherence spectrometer based on a hollow fiber compressor

    NASA Astrophysics Data System (ADS)

    Gueye, Moussa; Nillon, Julien; Crégut, Olivier; Léonard, Jérémie

    2016-09-01

    We describe a broadband transient absorption (TA) spectrometer devised to excite and probe, in the blue to UV range, vibrational coherence dynamics in organic molecules in condensed phase. A 800-nm Ti:Sa amplifier and a hollow fiber compressor are used to generate a 6-fs short pulse at 1 kHz. Broadband sum frequency generation with the fundamental pulse is implemented to produce a 400-nm, 8-fs Fourier limited short pulse. A UV-Vis white-light supercontinuum is implemented as a probe with intensity self-referencing to achieve a shot-noise-limited sensitivity. Rapid scanning of the pump-probe delay is shown very efficient in suppressing the noise resulting from low-frequency pump intensity fluctuations. Using either of the 800-nm or 400-nm broadband pulses as the pump for TA spectroscopy of organic molecules in solution, we resolve oscillatory signals down to the 320 nm probing wavelength with a 3200 cm-1 FWHM bandwidth. Their Fourier transformation reveals the corresponding molecular vibrational spectra. Finally, we demonstrate the use of this setup as a vibrational coherence spectrometer for the investigation of the vibrational dynamics accompanying the sub-ps C=C photoisomerization of a retinal-like molecular switch through a conical intersection.

  14. Dispersive liquid-liquid microextraction of thiram followed by microvolume UV-vis spectrophotometric determination

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, Saadat; Pourreza, Nahid; Larki, Arash

    2013-10-01

    A novel and simple method for the sensitive determination of trace amounts of fungicide thiram is developed by combination of dispersive liquid-liquid microextraction (DLLME) and microvolume UV-vis spectrophotometry. The method is based on the conversion of thiram to a yellow product in the presence of ethanolic potassium hydroxide and copper sulfate, and its extraction into CCL4 using DLLME technique. In this method the ethanol existing in ethanolic KOH plays as disperser solvent and a cloudy solution is formed by injection of only CCl4 as extractant solvent into sample solution. Under the optimum conditions, the calibration graph was linear over the range of 25-1000 ng mL-1 of thiram with limit of detection of 11.5 ng mL-1. The relative standard deviation (RSD) for 100 and 500 ng mL-1 of thiram was 2.7 and 1.1% (n = 8), respectively. The proposed method was successfully applied to determination of thiram in water and plant seed samples.

  15. Space weathering of asteroidal surfaces . Influence on the UV-Vis spectra

    NASA Astrophysics Data System (ADS)

    Kanuchova&, Z.; Baratta, G. A.; Garozzo, M.; Strazzulla, G.

    The surfaces of airless bodies in the Solar System are continuously altered by micrometeoroids bombardment and irradiation by solar wind, flares and cosmic particles. Major effects of this process - space weathering - are darkening and "reddening" of the spectra of surface materials. We have studied the changes induced by energetic ion irradiation, in the UV-Vis-NIR (0.2-0.98 mu m) reflectance spectra of targets selected to mimic the surfaces of airless bodies in the inner Solar System. Chosen targets are olivine pellets, pure or covered by a transparent organic polymer (polystyrene). We have also measured the changes induced by ion irradiation in the absorption coefficient of the polymer. We have measured the variations of the absorption coefficient (0.25-0.98 mu m) of polystyrene as a function of ion fluence. The diffuse reflectance spectra of irradiated samples covered by organics exhibit a much more significant variation than those of pure silicates. The spectra of targets made of olivine plus polystyrene can be fitted by using the measured absorption coefficient of polystyrene.

  16. Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions

    PubMed Central

    Wang, Ning; Tan, Furui; Zhao, Yu; Tsoi, Chi Chung; Fan, Xudong; Yu, Weixing; Zhang, Xuming

    2016-01-01

    On-ch