Relevant bibliographies by topics / NMR spectroscopic techniques

Academic literature on the topic 'NMR spectroscopic techniques'

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Published: 6 September 2023

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Journal articles on the topic "NMR spectroscopic techniques"

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Chang, C. T. Philip, Jinli Qiao, Songhua Chen, and A. Ted Watson. "Fracture Characterization with NMR Spectroscopic Techniques." Journal of Magnetic Resonance 126, no. 2 (June 1997): 213–20. http://dx.doi.org/10.1006/jmre.1997.1175.

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Lu, Yao, Yong-Chao Lu, Hong-Qin Hu, Feng-Jin Xie, Xian-Yong Wei, and Xing Fan. "Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods." Journal of Spectroscopy 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/8951658.

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Lignin is highly branched phenolic polymer and accounts 15–30% by weight of lignocellulosic biomass (LCBM). The acceptable molecular structure of lignin is composed with three main constituents linked by different linkages. However, the structure of lignin varies significantly according to the type of LCBM, and the composition of lignin strongly depends on the degradation process. Thus, the elucidation of structural features of lignin is important for the utilization of lignin in high efficient ways. Up to date, degradation of lignin with destructive methods is the main path for the analysis of molecular structure of lignin. Spectroscopic techniques can provide qualitative and quantitative information on functional groups and linkages of constituents in lignin as well as the degradation products. In this review, recent progresses on lignin degradation were presented and compared. Various spectroscopic methods, such as ultraviolet spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, for the characterization of structural and compositional features of lignin were summarized. Various NMR techniques, such as 1H, 13C, 19F, and 31P, as well as 2D NMR, were highlighted for the comprehensive investigation of lignin structure. Quantitative 13C NMR and various 2D NMR techniques provide both qualitative and quantitative results on the detailed lignin structure and composition produced from various processes which proved to be ideal methods in practice.
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Shah, A. M., and A. J. Rojivadiya. "Synthesis and Characterization of Imidazo[1,2-a]Pyrimidine." International Letters of Chemistry, Physics and Astronomy 52 (June 2015): 1–4. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.52.1.

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An efficient protocol for the synthesis of imidazo [1,2-a] pyrimidine was developed by using three component one-pot Biginelli synthesis. The synthesized compounds were characterized by spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and mass spectroscopy.
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Shah, A. M., and A. J. Rojivadiya. "Synthesis and Characterization of Imidazo[1,2-a]Pyrimidine." International Letters of Chemistry, Physics and Astronomy 52 (June 2, 2015): 1–4. http://dx.doi.org/10.56431/p-hnz44l.

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An efficient protocol for the synthesis of imidazo [1,2-a] pyrimidine was developed by using three component one-pot Biginelli synthesis. The synthesized compounds were characterized by spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and mass spectroscopy.
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Shah, A. M., and A. J. Rojivadiya. "An Expeditious Synthesis of 1,2,4-Triazolo[1,5-a]Pyrimidine." International Letters of Chemistry, Physics and Astronomy 51 (May 2015): 1–4. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.51.1.

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A simple, efficient, and diversity oriented synthesis of library of 1,2,4-triazolo [1,5-a] pyrimidine was undertaken using 5-amino,1,2,4-triazole as a building block. The synthesized analogues were fully characterized by known spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and mass spectroscopy.
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Shah, A. M., and A. J. Rojivadiya. "An Expeditious Synthesis of 1,2,4-Triazolo[1,5-<i>a</i>]Pyrimidine." International Letters of Chemistry, Physics and Astronomy 51 (May 15, 2015): 1–4. http://dx.doi.org/10.56431/p-p4100a.

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A simple, efficient, and diversity oriented synthesis of library of 1,2,4-triazolo [1,5-a] pyrimidine was undertaken using 5-amino,1,2,4-triazole as a building block. The synthesized analogues were fully characterized by known spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and mass spectroscopy.
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Pandiselvam, Ravi, Rathnakumar Kaavya, Sergio I. Martinez Monteagudo, V. Divya, Surangna Jain, Anandu Chandra Khanashyam, Anjineyulu Kothakota, et al. "Contemporary Developments and Emerging Trends in the Application of Spectroscopy Techniques: A Particular Reference to Coconut (Cocos nucifera L.)." Molecules 27, no. 10 (May 19, 2022): 3250. http://dx.doi.org/10.3390/molecules27103250.

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The number of food frauds in coconut-based products is increasing due to higher consumer demands for these products. Rising health consciousness, public awareness and increased concerns about food safety and quality have made authorities and various other certifying agencies focus more on the authentication of coconut products. As the conventional techniques for determining the quality attributes of coconut are destructive and time-consuming, non-destructive testing methods which are accurate, rapid, and easy to perform with no detrimental sampling methods are currently gaining importance. Spectroscopic methods such as nuclear magnetic resonance (NMR), infrared (IR)spectroscopy, mid-infrared (MIR)spectroscopy, near-infrared (NIR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, fluorescence spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy (RS) are gaining in importance for determining the oxidative stability of coconut oil, the adulteration of oils, and the detection of harmful additives, pathogens, and toxins in coconut products and are also employed in deducing the interactions in food constituents, and microbial contaminations. The objective of this review is to provide a comprehensive analysis on the various spectroscopic techniques along with different chemometric approaches for the successful authentication and quality determination of coconut products. The manuscript was prepared by analyzing and compiling the articles that were collected from various databases such as PubMed, Google Scholar, Scopus and ScienceDirect. The spectroscopic techniques in combination with chemometrics were shown to be successful in the authentication of coconut products. RS and NMR spectroscopy techniques proved their utility and accuracy in assessing the changes in coconut oil’s chemical and viscosity profile. FTIR spectroscopy was successfully utilized to analyze the oxidation levels and determine the authenticity of coconut oils. An FT-NIR-based analysis of various coconut samples confirmed the acceptable levels of accuracy in prediction. These non-destructive methods of spectroscopy offer a broad spectrum of applications in food processing industries to detect adulterants. Moreover, the combined chemometrics and spectroscopy detection method is a versatile and accurate measurement for adulterant identification.
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Laurent, W., J. M. Bonny, and J. P. Renou. "Muscle characterisation by NMR imaging and spectroscopic techniques." Food Chemistry 69, no. 4 (June 2000): 419–26. http://dx.doi.org/10.1016/s0308-8146(00)00051-0.

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Gjuroski, Ilche, Julien Furrer, and Martina Vermathen. "Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques." Molecules 26, no. 7 (March 30, 2021): 1942. http://dx.doi.org/10.3390/molecules26071942.

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Porphyrinic compounds are widespread in nature and play key roles in biological processes such as oxygen transport in blood, enzymatic redox reactions or photosynthesis. In addition, both naturally derived as well as synthetic porphyrinic compounds are extensively explored for biomedical and technical applications such as photodynamic therapy (PDT) or photovoltaic systems, respectively. Their unique electronic structures and photophysical properties make this class of compounds so interesting for the multiple functions encountered. It is therefore not surprising that optical methods are typically the prevalent analytical tool applied in characterization and processes involving porphyrinic compounds. However, a wealth of complementary information can be obtained from NMR spectroscopic techniques. Based on the advantage of providing structural and dynamic information with atomic resolution simultaneously, NMR spectroscopy is a powerful method for studying molecular interactions between porphyrinic compounds and macromolecules. Such interactions are of special interest in medical applications of porphyrinic photosensitizers that are mostly combined with macromolecular carrier systems. The macromolecular surrounding typically stabilizes the encapsulated drug and may also modify its physical properties. Moreover, the interaction with macromolecular physiological components needs to be explored to understand and control mechanisms of action and therapeutic efficacy. This review focuses on such non-covalent interactions of porphyrinic drugs with synthetic polymers as well as with biomolecules such as phospholipids or proteins. A brief introduction into various NMR spectroscopic techniques is given including chemical shift perturbation methods, NOE enhancement spectroscopy, relaxation time measurements and diffusion-ordered spectroscopy. How these NMR tools are used to address porphyrin–macromolecule interactions with respect to their function in biomedical applications is the central point of the current review.
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Maity, Sanhita, Ravi Kumar Gundampati, and Thallapuranam Krishnaswamy Suresh Kumar. "NMR Methods to Characterize Protein-Ligand Interactions." Natural Product Communications 14, no. 5 (May 1, 2019): 1934578X1984929. http://dx.doi.org/10.1177/1934578x19849296.

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Structural information pertaining to the interactions between biological macromolecules and ligands is of potential significance for understanding of molecular mechanisms in key biological processes. Recently, nuclear magnetic resonance (NMR) spectroscopic techniques has come of age and has widened its scope to characterize binding interactions of small molecules with biological macromolecules especially, proteins. NMR spectroscopy-based techniques are versatile due to their ability to examine weak binding interactions and for rapid screening the binding affinities of ligands with proteins at atomic resolution. In this review, we provide a broad overview of some of the important NMR approaches to investigate interactions of small organic molecules with proteins.
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Dissertations / Theses on the topic "NMR spectroscopic techniques"

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Zanca, Nicola <1985&gt. "NMR and MASS Spectroscopic Techniques for Source Apportionment of Atmospheric Particulate Matter." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8137/1/PhD%20Thesis%20Nicola%20Zanca.pdf.

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Aerosols are ubiquitous in the atmosphere, and play a key role in several environmental processes at local and global scale affecting visibility, air quality, and the climate system. In the present study, proton nuclear magnetic resonance (H-NMR) spectroscopy and aerosol mass spectrometry implemented by an “aerosol chemical speciation monitor” (ACMS) were employed to investigate the chemical composition of submicrometric aerosol collected during a series of intensive field campaigns and to resolve its composition into source-specific fractions including distinct types of primary and secondary organic aerosols (POA and SOA). During the first study, aerosol samples were collected in the Po Valley, in Bologna (urban site) and San Pietro Capofiume (rural site), during the summer 2012 (PEGASOS project) and fall, winter seasons 2013 (SUPERSITO campaigns). The results show that biomass burning POA and SOA dominate the composition of oxygenated organic aerosols in the Po Valley in the cold season, whereas humic-like substances (HULIS), related to chemically-aged SOA types, are prevalent in the summertime. In the second part of this thesis work, SOA samples were produced in laboratory using a flow tube reactor designed to simulate prolonged photochemical ageing. The samples were analyzed by H-NMR and high-liquid performance chromatography (HPLC) for the characterization of isoprene, α-pinene and naphthalene SOA products. The third part of this work was dedicated to two field campaigns at coastal and marine sites in the central Mediterranean region: the first one in Civitavecchia – the port of Rome, for the AIR-SEA Lab project -, and another one onboard the Amerigo Vespucci vessel during the project Dual Use Vespucci. Results showed that PM1 total concentration resulted only 22% lower over the open sea with respect to ports, but the fossil fuel component of OA (the hydrocarbon fraction) was much more enriched in harbors than in off-shore areas.
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Liitiä, Tiina. "Application of modern NMR spectroscopic techniques to structural studies of wood and pulp components." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/kemia/vk/liitia/.

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Bennet, Ian. "Evidence of dynamics and disorder using NMR-spectroscopic techniques applied to human Flap-Endonuclease-1." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19844/.

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Flap endonuclease 1 (FEN1) is a member of a 5’ nuclease superfamily involved in DNA replication and repair. FEN1 hydrolyses the phosphodiester bond one nucleotide into the duplex region of bifurcated double-flapped structures as found in lagging-strand DNA synthesis. These flap structures need to be cut in a very specific manner on the order of around 106 times per cell cycle. Therefore FEN1 is seen as an essential enzyme that maintains genomic integrity across all life forms. How FEN1 achieves its molecular recognition for a chemically very similar but structurally different DNA substrate and how it achieves catalysis on a biochemically relevant timescale are key questions to understand the protein system. This thesis describes some of the mechanistic studies used to understand how the structure and dynamics of hFEN1 relate to its function. It was proposed that T5 bacteriophage FEN was a catalytically perfect, or diffusion-limited enzyme, yet its main rate-limiting step after substrate binding was non-chemistry related. To ascertain whether this was true for hFEN1, the effect of leaving group pKa using 2’ modified double flapped substrates on rates of catalysis was measured. It was found that both apparent second order rates and first order single turnover rates of catalysis were insensitive to leaving group pKa. Furthermore by supplementing the reaction with glycerol, an unexpectedly high viscosity dependence was observed. The explanation for this is likely the presence of another physical step in the catalytic cycle affected by viscosity. Previous structural and biophysical studies of hFEN1 identified a helical arch, which was thought to be disordered as it could accommodate bulky 5’ flaps through it. Furthermore, the arch is key for positioning the 5’ flap into the active site. Using NMR spectroscopic techniques the solution state conformation of apo-hFEN1 was analysed. The arch was found to be disordered, but the C- terminal portion of it was transiently sampling α-helical φ,ψ space, while the other half was in an extended conformation. Another DNA recognition region, the α2-α3 loop was also found to be disordered. Various ligands and substrates were found to alter the structure and the dynamics of hFEN1. Addition of substrate DNA slowed the motion of the arch and α2-α3 loop to a millisecond timescale. Equally addition of a single monophosphate nucleotide had an effect on the dynamics of the top of the arch, despite binding in the active site. Furthermore, titration of calcium ions into the active site when DNA was present on the enzyme resulted in large perturbations to substrate recognition sites distant from the active site. This potentially links the specificity of these regions to activity within the active site.
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Scarfe, Graeme Bryan. "The in vivo metabolism of substituted anilines and acetanilides in rat using hyphenated NMR spectroscopic techniques." Thesis, Birkbeck (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325321.

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Tian, Ganghong. "Optimization of techniques for cardiac preservation: Phosphorus-31 NMR spectroscopic and functional studies in isolated rat and pig hearts." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/9571.

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The effects of cardioplegic and reperfusion conditions on energy metabolites and cardiac function were investigated in order to define better conditions for heart preservation (4 or 8 hrs). Myocardial energy metabolites (ATP, PCr and inorganic phosphate), intracellular pH and contractile function were followed using $\sp{31}$P NMR spectroscopy and left intra-ventricular balloon, respectively, during preservation and reperfusion in isolated pig and rat hearts. These hearts were subjected to various conditions of cardioplegia and reperfusion which involved re-arrest perfusion following ischemic preservation, increased concentrations of buffer and Mg$\sp{++}$ in cardioplegic and reperfusion solutions, and an intracellular-type cardioplegic solution. The effect of re-arrest perfusion was tested by comparing the recovery of energy metabolites and contractile function between pig hearts subjected to a secondary cardioplegic solution (S-C-S) prior to Krebs-Henseleit (K-H) solution and those reperfused with K-H solution alone after 8 hours of ischemic preservation at 12$\sp\circ$C. The levels of ATP and PCr during reperfusion in both groups of hearts were comparable whereas the left ventricular developed pressure was significantly higher in the hearts reperfused with S-C-S than in those reperfused only with K-H solution. The reperfusion-induced ventricular fibrillation that occurred in K-H reperfused hearts was prevented by re-arrest perfusion. A cardioplegic solution containing 150 mmol/L MOPS (higher buffer cardioplegic solution) helped to maintain intracellular pH during 8 hours of ischemic preservation. However, it did not affect the levels of energy metabolites during preservation and contractile function during reperfusion. The effects of 16 mmol/L Mg$\sp{++}$ in cardioplegic and reperfusion solution were evaluated using both rat and pig hearts. In working rat hearts, 16 mmol/L Mg$\sp{++}$ in cardioplegic solution did not alter myocardial oxygen consumption and contractile function following 30 minutes of normothermic preservation. Moreover, Langendorff pig hearts preserved with either 0 or 16 mmol/L Mg$\sp{++}$ cardioplegic solution showed similar decrements in energy metabolites during 4 hours of ischemic preservation at 12$\sp\circ$C and recovery of contractile function during reperfusion while 16 mmol/L Mg$\sp{++}$ in K-H solution resulted in a dramatic decline of contractile function. Furthermore, 16 mmol/L Mg$\sp{++}$ in S-C-S also did not affect the levels of high energy phosphates and contractile function during reperfusion. At 4$\sp\circ$C the pig hearts stored with either University of Wisconsin solution (UW, an intracellular-type cardioplegic solution) or St Thomas' solution (an extracellular-type cardioplegic solution) showed comparable changes in energy metabolites during 8 hours of preservation and a similar recovery of contractile function during reperfusion. However, at 12$\sp\circ$C, hearts stored in UW solution showed rapid decrease in ATP and PCr during preservation and significantly poorer functional recovery during reperfusion; four of eight hearts stored in UW solution at 12$\sp\circ$C showed the "stone heart" phenomenon with disappearance of PCr and ATP upon reperfusion. The addition of 0.5 mmol/L Ca$\sp{++}$ to UW solution significantly improved contractile function and prevented the occurrence of the "stone heart" phenomenon with stable levels of high energy phosphates. (Abstract shortened by UMI.)
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Yee, Sidney. "Solution-State Proton Nuclear Magnetic Resonance (NMR) Spectroscopic Studies of the Active Site of Myoglobins in Various Ligated States: Models for Macromolecule-Substrate Binding and Advancement of Paramagnetic NMR Techniques." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/1253.

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This work focuses on pigmy sperm whale and horse myoglobins (Mbs), which are distinguished by a single heme pocket residue variant in the CD3 position, when the heme iron is in the +3 oxidation state (i.e. the met form). The strategy employed is as follows: (i) assign heme peripheral protons; (ii) assign the amino acid residues from the heme cavity; (iii) assess the dynamics of ligand binding in the active site by means of hydrogen Iability, solvent isotope effects, and heme-insertion isomer trapping, all by NMR methods. The results of these studies portray dynamic solution structure of the Mb ligand binding site, and provide a set of standard parameters for the studies of larger hemoproteins. The findings are also important for understanding protein-ligand interactions in general. My research investigates the mixed spin metazido and metimidazole complexes of Mbs for the following reasons. First, the allosteric properties of hemoglobin arise mainly from the transition between its two possible quaternary structures. This can be studied by paramagnetic NMR because it is one of the most sensitive tools in terms of changes in the molecular and/or electronic structure of the heme. Second, both the N₃- and imidazole (lm-) complexes are good compromises, in terms of sizes, between the small diatomic oxygen or CN⁻ molecules and the bulky phenyl group. Thus, we can determine the influence of ligand size on structural perturbation of the Heme crevice by comparison among the different size groups. Third, the saturation-transfer phenomenon between metMbIm and metMbH₂0 provides a route to assignments in metMbH₂0 by using assignments of metMbIm. This is crucial because metMbH₂0 is the basis of theoretical calculations of the isotropic shift due to axial ligand field in pure high-spin hemoproteins. Finally, the importance of the metMbIm is underscored by the fact that it is a bis-imidazolium complex, which can then serve as a model other bis-histidyl proteins. Most of the heme peripheral resonances of metEqMbIm and metEqMbN₃ were identified by means of two-dimensional NOESY,COSY, and EXSY spectroscopy. The strongly relaxed upfield protons in metMbIm were assigned based on steady-state 1D NOE and T₁ experiments. Based on the results from metMblm in which saturation transfer of one upfield resonance led to two different free ligand peaks, bound Im equilibration was envisioned and proven by the divergence of broad downfield heme methyl peaks into two peaks each, showing distinctive population preference of each isomer. Dicyanoheme probe, as well as hydrogen Iability comparison studies between pigmy sperm whale Mb and horse Mb in the azido and imidazole states, asserts that single variant pocket residue CD3 is crucial in gating the ligand mobility into and out of the active site. The assignments of heme peripheral and upfield resonances enabled the subsequent assignments of some heme pocket amino acid residues. The facile exchange of bound Im with solvent H₂0 lays the ground work for identification of heme pocket residues in metMbH₂0. Furthermore, while deuterated heme previously allowed only assignment of the non-diastereomeric specific heme 2-vinyl β proton, saturation-transfer from horse imidazole Mb affords the specific identification of 2Hᵦt.
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Gudmundson, Erik. "Signal Processing for Spectroscopic Applications." Doctoral thesis, Uppsala universitet, Avdelningen för systemteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-120194.

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Spectroscopic techniques allow for studies of materials and organisms on the atomic and molecular level. Examples of such techniques are nuclear magnetic resonance (NMR) spectroscopy—one of the principal techniques to obtain physical, chemical, electronic and structural information about molecules—and magnetic resonance imaging (MRI)—an important medical imaging technique for, e.g., visualization of the internal structure of the human body. The less well-known spectroscopic technique of nuclear quadrupole resonance (NQR) is related to NMR and MRI but with the difference that no external magnetic field is needed. NQR has found applications in, e.g., detection of explosives and narcotics. The first part of this thesis is focused on detection and identification of solid and liquid explosives using both NQR and NMR data. Methods allowing for uncertainties in the assumed signal amplitudes are proposed, as well as methods for estimation of model parameters that allow for non-uniform sampling of the data. The second part treats two medical applications. Firstly, new, fast methods for parameter estimation in MRI data are presented. MRI can be used for, e.g., the diagnosis of anomalies in the skin or in the brain. The presented methods allow for a significant decrease in computational complexity without loss in performance. Secondly, the estimation of blood flow velo-city using medical ultrasound scanners is addressed. Information about anomalies in the blood flow dynamics is an important tool for the diagnosis of, for example, stenosis and atherosclerosis. The presented methods make no assumption on the sampling schemes, allowing for duplex mode transmissions where B-mode images are interleaved with the Doppler emissions.
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Stonehouse, Jonathan. "New techniques in NMR spectroscopy." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360628.

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Hughes, Colan Evan. "New techniques in NMR spectroscopy." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297524.

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Rogerson, Alexandria. "New techniques in diffusion-ordered NMR spectroscopy." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/new-techniques-in-diffusionordered-nmr-spectroscopy(aa3eaee0-984b-4434-b460-8c3118a7c3b2).html.

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The analysis of mixtures is a subject that spans several different analytical techniques. In NMR, a powerful technique for this analysis is Diffusion-Ordered NMR Spectroscopy (DOSY), in which signals from different chemical species can be distinguished by their different diffusion coefficients. DOSY NMR allows an analysis of mixture components and their interactions in a non-invasive way and is proving to be an accurate and time effective method for looking at mixtures.An in-depth analysis of DOSY NMR is presented using the commercial mixture “monoacetin”. The chemically cognate species in this mixture produce complex and overlapping multiplet signals in 1H NMR that are difficult to assign and interpret. A previous analysis of this mixture used 1H NMR together with Liquid Chromatography (LC) and Gas Chromatography (GC) to identify the components present, but failed to provide complete assignments of all the signals. Here, the possibility of using DOSY as an alternative to hyphenated techniques is examined, and it is shown that a full analysis of the spectrum of “monoacetin” is possible with careful selection of experimental parameters and processing techniques, without recourse to chromatography. DOSY NMR can be ineffective when signals overlap and/or diffusion coefficients are similar. Many methods have been proposed to overcome these problems, and some of these are presented here. In order to increase resolving power, it is possible to gather further information about a mixture and incorporate this into diffusion experiments as another dimension. This creates a 3D dataset that can be analysed using a multiway method, such as PARAFAC, to extract the component spectra. This method is explored for the mixture “monoacetin” that has been partially separated by high-performance liquid chromatography. Resolution of two out of four components was achieved from poor HPLC separation; the decomposition obtained the component spectra, diffusional decay and HPLC elution profile for these components. Improved HPLC separation should result in further resolution.Diffusion coefficients of different mixture species can be manipulated by changing the matrix in which they diffuse: Matrix-Assisted DOSY (MAD). Previous techniques have involved either improving resolution in the diffusion domain or aiming to improve resolution in chemical shift. A method is presented here that simultaneously addresses both problems in a chemically-selective way, using lanthanide shift reagents. The chemically-selective binding of the LSR to mixture components can both enhance chemical shift dispersion and increase diffusion resolution in DOSY. This neatly deals with the two main drawbacks of the DOSY experiment, and is demonstrated using a mixture of an alkane, alcohol and aldehyde. The manipulation of a molecule’s electrostatic charge through pH control has been investigated, where small ions with a high charge density would be highly solvated, resulting in a change in D. The effect, however, was not measurable and so the indirect effect of pH on the interaction of charged species with the cationic micelle CTAB is presented, where an increase in resolution between of mixture of aspirin and salicylic acid is achieved.Although DOSY NMR is a powerful tool for mixture analysis, in recent years it has been used for studying molecular interactions. An example of this is presented here where species aggregate under specific conditions, a process identified by DOSY NMR.
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Books on the topic "NMR spectroscopic techniques"

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1954-, Jones Christopher, Mulloy Barbara, and Thomas Adrian H, eds. Spectroscopic methods and analyses: NMR, mass spectrometry, and metalloprotein techniques. Totowa, N.J: Humana Press, 1993.

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Dolphin, Bruch Martha, ed. NMR spectroscopy techniques. 2nd ed. New York: M. Dekker, 1996.

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R, Dybowski C., and Lichter Robert L, eds. NMR spectroscopy techniques. New York: M. Dekker, 1987.

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G, Reid David, ed. Protein NMR techniques. Totowa, N.J: Humana Press, 1997.

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Protein NMR techniques. 3rd ed. New York, N.Y: Humana Press, 2012.

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Jean-Noël, Barbotin, and Portais Jean-Charles, eds. NMR in microbiology: Theory and applications. Wymondham: Horizon Scientific, 2000.

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1942-, Bell Alexis T., and Pines Alexander 1945-, eds. NMR techniques in catalysis. New York: M. Dekker, 1994.

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Lian, Lu-Yun, and Gordon Roberts, eds. Protein NMR Spectroscopy: Practical Techniques and Applications. Chichester, UK: John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119972006.

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In vivo NMR spectroscopy: Principles and techniques. Chichester: Wiley, 1998.

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In vivo NMR spectroscopy: Principles and techniques. 2nd ed. Chichester, West Sussex, England: John Wiley & Sons, 2007.

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Book chapters on the topic "NMR spectroscopic techniques"

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Brunner, Eike, and Harry Pfeifer. "NMR Spectroscopic Techniques for Determining Acidity and Basicity." In Acidity and Basicity, 1–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/3829_2007_016.

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Ward, I. M. "Determination of molecular orientation by spectroscopic techniques." In Characterization of Polymers in the Solid State I: Part A: NMR and Other Spectroscopic Methods Part B: Mechanical Methods, 81–115. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/3-540-13779-3_18.

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Farrell, Harold M., and Adela Mora-Gutierrez. "κ-Carrageenan Interaction with Bovine and Caprine Caseins as Shown by Sedimentation and NMR Spectroscopic Techniques." In ACS Symposium Series, 93–114. Washington, DC: American Chemical Society, 2006. http://dx.doi.org/10.1021/bk-2006-0935.ch006.

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Renou, J. P., and G. Monin. "NMR Spectroscopy Perspectives." In Application of NMR Techniques on the Body Composition of Live Animals, 163–69. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-011-9705-2_14.

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Chandrakumar, Narayanan, and Sankaran Subramanian. "Multiple-Quantum Spectroscopy." In Modern Techniques in High-Resolution FT-NMR, 226–59. New York, NY: Springer New York, 1987. http://dx.doi.org/10.1007/978-1-4612-4626-8_5.

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Duer, Melinda J. "Essential Techniques for Spin-½ Nuclei." In Solid-State NMR Spectroscopy Principles and Applications, 73–110. Oxford, UK: Blackwell Science Ltd, 2007. http://dx.doi.org/10.1002/9780470999394.ch2.

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Keizers, Peter H. J., and Marcellus Ubbink. "Paramagnetic Tools in Protein NMR." In Protein NMR Spectroscopy: Practical Techniques and Applications, 193–219. Chichester, UK: John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119972006.ch6.

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Cheung, Tony, and Vasudevan Ramesh. "Biomolecular NMR Spectroscopy and Structure Determination of DNA." In Biomolecular and Bioanalytical Techniques, 421–69. Chichester, UK: John Wiley & Sons, Ltd, 2019. http://dx.doi.org/10.1002/9781119483977.ch17.

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Guntert, Peter. "Calculation of Structures from NMR Restraints." In Protein NMR Spectroscopy: Practical Techniques and Applications, 159–92. Chichester, UK: John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119972006.ch5.

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Kozak-Reiss, G. "NMR Spectroscopy. Applications in Human Medicine." In Application of NMR Techniques on the Body Composition of Live Animals, 41–49. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-011-9705-2_4.

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Conference papers on the topic "NMR spectroscopic techniques"

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Albuquerque, Ana Carolina Ferreira de, José Walkimar de Mesquita Carneiro, and Fernando Martins dos Santos Junior. "Estudo do tautomerismo ceto-enólico da 7-epi-clusianona através de cálculos teóricos de deslocamentos químicos de RMN." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol202063.

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The properties of natural products, including their biological and pharmacological activities, are directly correlated with their chemical structures. Thus, a correct structural characterization of these compounds is a crucial step to the understanding of their biological activities. However, despite the recent advances in spectroscopic techniques, structural studies of natural products can be challenging. This way, theoretical calculations of Nuclear Magnetic Resonance (NMR) parameters (such as chemical shifts and coupling constants) have proven to be a powerful and low-cost tool for the aid to experimental techniques traditionally used for the structural characterization of natural products. One of the several applications of quantum-mechanical calculations of NMR parameters is the study of tautomerism. Since chemical shifts are sensitive to the tautomeric equilibrium, this technique can provide crucial informations. In this work, it was applied a protocol for theoretical calculations of ¹³C chemical shifts in order to study the tautomerism of the natural product 7-epi-clusianone, isolated from Rheedia gardneriana. This protocol consists in a Monte Carlo conformational search, followed by geometry optimization and shielding tensors calculations, both using a density functional level of theory. After comparison of theoretical and experimental data, it was possible to confirm the two tautomers present in equilibrium in the experimental solution. Furthermore, this study highlights how this theoretical protocol can be an effective method in identifying the preferred tautomeric form in solution.
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"A 13C NMR Spectroscopic Study on the Reparation of Acid and Ester Groups in MPEG Type PCEs Prepared via Radical Copolymerization and Grafting Techniques." In SP-302: Eleventh International Conference on Superplasticizers and Other Chemical Admixtures in Concrete. American Concrete Institute, 2015. http://dx.doi.org/10.14359/51688082.

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Guha, Avishek, and Ingmar Schoegl. "Limited View Tomography of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy: Simulation of an Algebraic Reconstruction Technique." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89507.

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Temperature and concentration distributions of a simulated flame were reconstructed with the help of computer tomography and tunable diode laser absorption spectroscopy (TDLAS). Reconstructions were based on the simulated numerical values of temperature and concentration of a stationary flame. Integrated absorption measurements along the line-of-sight (LOS) across the flames due to absorption by water vapor (H2O) in the near infra-red (NIR) region, specifically the 6930–6940 cm−1 range, were simulated to obtain the projection values for tomography. Spectroscopic parameters for the absorptions transitions, such as line-strengths, transition wavenumbers, collisional broadening coefficients and coefficients for their temperature dependency were selected from the HITRAN 2004 database. Simulated LOS data are inverted using a multiplicative algebraic reconstruction technique (MART), which are known to outperform traditional filtered back projection methods for cases with limited numbers of views. Based on spatially resolved reconstructions of spectroscopic data, temperature and concentration distributions are calculated using the wavelength modulation spectroscopy with second harmonic detection (WMS-2f) technique. A parametric study based on the number of views, orientation of views and number of rays per view required by the ART is performed in order to assess requirements for an acceptable reconstruction.
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Romero, Pedro, Larisa Tagarieva, Loraine Ramos, Evgeny Sergeev, and Shaikha Al-Turkey. "Case Study: Petrophysical Characterization in Unconventional Reservoir in the Burgan Field." In Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/32119-ms.

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Abstract Thanks to the evolution of the technology and techniques to characterize organic rich shales, various options are available to perform a petrophysical evaluation, ranging from the most basic to the most complex, advanced ones. A robust petrophysical model is critical for the accuracy of the reservoir characterization; therefore, obtaining a reliable petrophysical analysis based on well logging data that can also support reservoir modeling and early wellsite decisions, was a key objective for this well drilled in an unconventional reservoir in the Burgan Field. For these reasons, technologically advanced logging services like Nuclear Magnetic Resonance and Nuclear Spectroscopy, along with conventional ones, including Spectral Gamma Ray, were logged in this well. The problem, then, is connecting all the valuable information obtained from different sources to define a petrophysical model. Are all sources reaching the same conclusion? This study aims to find how these different technologies and techniques can be interconnected to build a strong petrophysical model. Along with advanced technology, conventional logs were analyzed with the Organic Shale Petrophysics (OSP) technique which is based on the Gas Research Institute. Water saturation was obtained from NMR data using the T1T2 maps and DT2 maps and Blind Source Separation based on Independent Component Analysis (BSS-ICA). The most relevant results of the petrophysical analysis are as follows: Improvement in Fluid Saturations and Analysis:. The DT2 and T1T2 maps proved to resolve the fluid components in the organic matter rich section of the reservoir. Kerogen indicators identified with the Spectral Gamma Ray, OSP analysis and the NMR undercall porosity are in good agreement. The fluid saturation model applied to the 2D-NMR results and T1T2 maps, was iteratively improved based on the cross-correlation between Organic Carbon provided from Nuclear Spectroscopy (NS) and undercall porosity from NMR. NS-NMR data consistency: In this regard, the Organic Carbon from Nuclear Spectroscopy analysis matches with the NMR undercall porosity, proving the consistency of the log data and the applied analyses. In addition, a machine learning tool BSS-ICA was used to determine from the T2 spectra the independent spectral component of the hydrocarbon and its saturation, that shows good agreement with the results obtained with the traditional 2D NMR. This study proves that NMR data is key in the petrophysical evaluation of organic rich shales specifically for water saturation. The values of cementation exponent, m, and saturation exponent, n, used in the OSP Archie-based saturation model were confirmed with NMR data. These results, along with Nuclear Spectroscopy data, can be used to future optimization of Organic Shale Petrophysics ( OSP), to obtain a more precise petrophysical evaluation. This is will be extremely beneficial since these optimized parameters can be used for calibration when advance technology is not available.
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Romero, Pedro, Larisa Tagarieva, Loraine Ramos, Evgeny Sergeev, and Shaikha Al-Turkey. "Case Study: Petrophysical Characterization in Unconventional Reservoir in the Burgan Field." In Offshore Technology Conference. OTC, 2022. http://dx.doi.org/10.4043/32119-ms.

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Abstract Thanks to the evolution of the technology and techniques to characterize organic rich shales, various options are available to perform a petrophysical evaluation, ranging from the most basic to the most complex, advanced ones. A robust petrophysical model is critical for the accuracy of the reservoir characterization; therefore, obtaining a reliable petrophysical analysis based on well logging data that can also support reservoir modeling and early wellsite decisions, was a key objective for this well drilled in an unconventional reservoir in the Burgan Field. For these reasons, technologically advanced logging services like Nuclear Magnetic Resonance and Nuclear Spectroscopy, along with conventional ones, including Spectral Gamma Ray, were logged in this well. The problem, then, is connecting all the valuable information obtained from different sources to define a petrophysical model. Are all sources reaching the same conclusion? This study aims to find how these different technologies and techniques can be interconnected to build a strong petrophysical model. Along with advanced technology, conventional logs were analyzed with the Organic Shale Petrophysics (OSP) technique which is based on the Gas Research Institute. Water saturation was obtained from NMR data using the T1T2 maps and DT2 maps and Blind Source Separation based on Independent Component Analysis (BSS-ICA). The most relevant results of the petrophysical analysis are as follows: Improvement in Fluid Saturations and Analysis:. The DT2 and T1T2 maps proved to resolve the fluid components in the organic matter rich section of the reservoir. Kerogen indicators identified with the Spectral Gamma Ray, OSP analysis and the NMR undercall porosity are in good agreement. The fluid saturation model applied to the 2D-NMR results and T1T2 maps, was iteratively improved based on the cross-correlation between Organic Carbon provided from Nuclear Spectroscopy (NS) and undercall porosity from NMR. NS-NMR data consistency: In this regard, the Organic Carbon from Nuclear Spectroscopy analysis matches with the NMR undercall porosity, proving the consistency of the log data and the applied analyses. In addition, a machine learning tool BSS-ICA was used to determine from the T2 spectra the independent spectral component of the hydrocarbon and its saturation, that shows good agreement with the results obtained with the traditional 2D NMR. This study proves that NMR data is key in the petrophysical evaluation of organic rich shales specifically for water saturation. The values of cementation exponent, m, and saturation exponent, n, used in the OSP Archie-based saturation model were confirmed with NMR data. These results, along with Nuclear Spectroscopy data, can be used to future optimization of Organic Shale Petrophysics ( OSP), to obtain a more precise petrophysical evaluation. This is will be extremely beneficial since these optimized parameters can be used for calibration when advance technology is not available.
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Patonay, Gabor, Richard J. Williams, and Dana Shealy. "Near-Infrared Fluorescence Techniques in Analytical Chemistry." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/laca.1992.mb1.

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The near-infrared (NIR) region is advantageous due to lower interference since there are only a few groups of compounds that can fluoresce. Examples of analytical application of NIR fluorescence with emphasis on laser diode spectroscopy will be given.
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Su, Haw-Lih, Rajeesha Rajan, Yousef Mohammad Hijji, Mohammad Ibrahim Ahmad Ibrahim, and Mohammed Hussain S. A. Alsafran. "Detecting Organic Nitrogen with 1H-15N HMBC Spectra." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0038.

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NMR spectroscopy has been the most important tool for organic chemistry research, providing detailed structure information. While 1H and 13C NMR spectra were frequently measured, 15N NMR spectra were relatively rare, even though nitrogen is commonly observed in organic molecules. This is due to the low gyromagnetic ratio and nature abundance. Usually 15N NMR spectra are observed when the sample is in very high concentration or the nitrogen is enriched with 15N isotope. HMBC is one of the 2D NMR techniques, measuring the through-bond correlations inside a molecule. 1H-15N HMBC actually collects a series of measurements of 1H NMR spectra with 15N information. Therefore, HMBC could get stronger signals than 15N signals and provide the opportunity for the indirect measurement of 15N signals.
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Gomes, Matheus G. R., Hélio F. dos Santos, and Diego F. S. Paschoal. "Predicting Co-59 NMR Chemical Shit using the NMR-DKH Basis Sets." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol2020179.

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The cobalt-59 nucleus is an NMR active nucleus with the nuclear spin I = 7/2 and has a natural abundance of 100 %. It is an important nucleus because it has ease of detectable NMR signals both liquid and solid-state. The Co-59 NMR chemical shift range is one of the largest known in NMR spectroscopy, spanning some 18,000 ppm or more. However, Co-59 NMR is an extremely sensitive technique to external factors such as pressure, temperature, and others. Therefore, predicting Co-59 NMR chemical shift might be useful to assist experimentalists in the structural characterization. In the present study, we propose a new NMR-DKH basis set for Co atom to predict NMR chemical shift in Co complexes. Besides, we proposed a computational protocol (Functional DFT/Co basis set/Ligands basis set) for the prediction of the structure and, later, for the prediction of the Co-59 NMR chemical shift using 6 Co complexes as model systems. The results show that the computational protocol (NMR/structure) GIAO-B3LYP/NMR-DKH/IEF-PCM(UFF)//CAM-B3LYP/LANL2DZ/jorge-DZP/IEF-PCM(UFF) presents a mean relative deviation (DRM) of 1.48% for the structure, a mean absolute deviation (MAD) of 101 ppm and a DRM of 1.2% for the Co-59 chemical shift. Finally, the protocol was corrected by a linear regression model giving a MAD and MRD of 57 ppm and 0.7%, respectively.
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Watson, R., M. Kohl, P. O'Brien, S. Lawrence, DT Delpy, and M. Cope. "Fetal Brain Oxygenation during Labor studied by Frequency Domain Spectroscopy." In Biomedical Optical Spectroscopy and Diagnostics. Washington, D.C.: Optica Publishing Group, 2006. http://dx.doi.org/10.1364/bosd.1996.ap14.

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Hypoxic-ischemia of the brain (tissue oxygen deficiency due to obstructed circulation) during birth can result in neurological impairment and consequently patients that may require specialised care for the remainder of their life. An accurate method for measuring fetal brain oxygenation is therefore required. Traditional clinical techniques do not directly measure cerebral oxygenation and are unpleasant for both the mother and fetus. Near infrared (NIR) spectroscopy is a technique that allows changes in tissue chromophore concentrations to be measured non-invasively. Most NIR spectrometers use algorithms which assume that the optical pathlength of the light in the tissue does not change during the measurement. In the area of fetal NIR spectroscopy, it is of interest to determine whether contraction induced optical pathlength changes produce significant errors in the estimated concentration changes. An intensity modulated optical spectrometer (MOS) can provide optical pathlength information in addition to the pure intensity data provided by traditional NIR spectrometers. An MOS is used here to investigate the influence of contractions on the change in the oxy- and deoxy-hemoglobin status in the fetal brain. It was found that in most cases the changes in optical pathlength did not contribute significantly to any error. It appears that the pathlength changes are primarily due to contraction induced absorption changes. It also appears that artefactual pathlength and absorption changes, which occur due to maternal movement, while to0 complicated to physically characterise are readily recognisable in the raw data.
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Schrader, Bernhard, Andreas Hoffmann, Martin Tischer, Rolf Podschadlowski, and Arno Simon. "Optimization Of The Sample Technique For NIR FT Raman Spectroscopy." In Intl Conf on Fourier and Computerized Infrared Spectroscopy, edited by David G. Cameron. SPIE, 1989. http://dx.doi.org/10.1117/12.969418.

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Reports on the topic "NMR spectroscopic techniques"

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Yee, Sidney. Solution-State Proton Nuclear Magnetic Resonance (NMR) Spectroscopic Studies of the Active Site of Myoglobins in Various Ligated States: Models for Macromolecule-Substrate Binding and Advancement of Paramagnetic NMR Techniques. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.1252.

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Henderson, Terry J., and David B. Cullinan. Trace Level Detection of Chemical Weapons Convention Compounds by Two-Dimensional C13-NMR Spectroscopy using a Cryogenic Probehead and H1-Detection Techniques. Fort Belvoir, VA: Defense Technical Information Center, October 2009. http://dx.doi.org/10.21236/ada507477.

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Agassi, Menahem, Michael J. Singer, Eyal Ben-Dor, Naftaly Goldshleger, Donald Rundquist, Dan Blumberg, and Yoram Benyamini. Developing Remote Sensing Based-Techniques for the Evaluation of Soil Infiltration Rate and Surface Roughness. United States Department of Agriculture, November 2001. http://dx.doi.org/10.32747/2001.7586479.bard.

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The objective of this one-year project was to show whether a significant correlation can be established between the decreasing infiltration rate of the soil, during simulated rainstorm, and a following increase in the reflectance of the crusting soil. The project was supposed to be conducted under laboratory conditions, using at least three types of soils from each country. The general goal of this work was to develop a method for measuring the soil infiltration rate in-situ, solely from the reflectance readings, using a spectrometer. Loss of rain and irrigation water from cultivated fields is a matter of great concern, especially in arid, semi-arid regions, e.g. much of Israel and vast area in US, where water is a limiting factor for crop production. A major reason for runoff of rain and overhead irrigation water is the structural crust that is generated over a bare soils surface during rainfall or overhead irrigation events and reduces its infiltration rate (IR), considerably. IR data is essential for predicting the amount of percolating rainwater and runoff. Available information on in situ infiltration rate and crust strength is necessary for the farmers to consider: when it is necessary to cultivate for breaking the soil crust, crust strength and seedlings emergence, precision farming, etc. To date, soil IR is measured in the laboratory and in small-scale field plots, using rainfall simulators. This method is tedious and consumes considerable resources. Therefore, an available, non-destructive-in situ methods for soil IR and soil crusting levels evaluations, are essential for the verification of infiltration and runoff models and the evaluation of the amount of available water in the soil. In this research, soil samples from the US and Israel were subjected to simulated rainstorms of increasing levels of cumulative energies, during which IR (crusting levels) were measured. The soils from the US were studied simultaneously in the US and in Israel in order to compare the effect of the methodology on the results. The soil surface reflectance was remotely measured, using laboratory and portable spectrometers in the VIS-NIR and SWIR spectral region (0.4-2.5mm). A correlation coefficient spectra in which the wavelength, consisting of the higher correlation, was selected to hold the highest linear correlation between the spectroscopy and the infiltration rate. There does not appear to be a single wavelength that will be best for all soils. The results with the six soils in both countries indeed showed that there is a significant correlation between the infiltration rate of crusted soils and their reflectance values. Regarding the wavelength with the highest correlation for each soil, it is likely that either a combined analysis with more then one wavelength or several "best" wavelengths will be found that will provide useful data on soil surface condition and infiltration rate. The product of this work will serve as a model for predicting infiltration rate and crusting levels solely from the reflectance readings. Developing the aforementioned methodologies will allow increased utilization of rain and irrigation water, reduced runoff, floods and soil erosion hazards, reduced seedlings emergence problems and increased plants stand and yields.
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Nuclear Magnetic Resonance Spectroscopy. ConductScience, November 2019. http://dx.doi.org/10.55157/cs20191121.

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Two molecules may have the same number and type of atoms, but their properties would change depending on how they are arranged (i.e., the bonds linking them and their orientation). As an example, Ethanol and Dimethyl ether, both have one oxygen, two carbon, and six hydrogen atoms, but the structures and properties of both these compounds are different. Ethanol exists as a liquid and Dimethyl ether, on the other hand, is a poisonous gas . Thus, it is crucial for scientists to identify the exact structure of the compounds in order to understand their properties. Nuclear Magnetic Resonance (NMR) spectroscopy is a technique used to precisely identify the molecular structure of the compound . NMR results for unknown compounds can be scanned with respect to a library of known compounds to reveal the identity .
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Honey authenticity: collaborative data sharing feasibility study. Food Standards Agency, January 2023. http://dx.doi.org/10.46756/sci.fsa.fbt231.

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According to the UN,1 there are more than 90 million managed beehives around the world producing about 1.9 million tonnes of honey worth more than £5 billion a year. That honey will then be packaged, as single origin or a blend of honey from different sources, and sold for consumption. Given the size of the market and the immense environmental benefits of beekeeping – three out of four crops depend on pollination by bees – it is an industry on which both livelihoods and lives depend. Target for adulteration As a labour-intensive, high-value expensive product with an often complex supply chain, honey is subject to internationally and nationally agreed definitions – and is a target for adulteration. Testing honey is therefore critical, but there is no single universal analytical method available which is capable of detecting all types of adulteration with adequate sensitivity. A variety of methods are used to detect honey adulteration, each test has strengths and weaknesses, and there are issues with interpretation. NMR analysis Testing for honey adulterated with added sugars may be based on analytical techniques using analytical tools, such as those using nuclear magnetic resonance spectroscopy (NMR). This is especially helpful in detecting certain types of adulteration, such as the addition of cane or beet sugars. Bees generally forage on plants that use the same photosynthetic pathway as beet sugars. This makes it difficult for traditional tests based on isotopic differences to provide effective results. The ‘chemical fingerprint’ provided by NMR is specific to the sample that has been tested and can be compared with the fingerprint from other sample results enabling the user to assess consistency. Reference databases Interpretation of results depends on comparison against a reference database of authenticated samples. The reference database needs to be representative of the variation that can occur, which includes differing beekeeping practices, origins, seasonality and variations in climate. Information is also needed on the collection of reference samples, curation of databases, interpretation and reporting of data. The nature of the reference databases is key to understanding how the results have been interpreted. However, these reference databases are owned by and commercially sensitive for the testing laboratories that have developed them. How can such data be shared in a trustworthy way between key stakeholders along the honey and analytical supply chain so that all parties can have confidence in honey authenticity test results? This research is looking into the implications of these hidden databases, especially in terms of the trust related to the validation certificates and the value that they have in the honey supply chain.
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