• Title/Summary/Keyword: NMR

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Theory of NMR Spectoscopy and Its Application in Geoenvironmental Sciences (NMR 분광법의 원리와 지구환경과학에의 응용)

  • 김영규
    • The Journal of the Petrological Society of Korea
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    • v.10 no.3
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    • pp.233-245
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    • 2001
  • With the advent of super-conducting magnet, NMR spectroscopy becomes a very important tool in geology as well as in chemistry. $^{29}Si$ and $^{27}Al$ which are the main components of minerals and contain structural informations, are useful major targets for the NMR study in geology, but some other elements including alkali cations such as $^{23}Na$ are also one of them. NMR can be applied to many different fields. For example, it can be applied to study smaller range of structure (in molecular level) than XRD and TEM. NMR provides us with structural informations such as order-disorder in Al and Si distribution, oxygen coordination number, and distribution of other cations. Another important information that we can obtain from NMR is not only the static structural informations, but also the molecular dynamics. This dynamic informations of molecules also enable us to figure out the frequency of molecular motion and activation energy. Structure of amorphous minerals and chemistry and structure of natural organic materials are also studied by NMR.

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Purity assessment using quantitative NMR: establishment of SI traceability in organic analysis

  • Choi, Kihwan
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.1
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    • pp.30-37
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    • 2020
  • Quantitative nuclear magnetic resonance (qNMR) has been gaining attention as a purity assessment method. In particular, qNMR is recognized as the primary method to realize the Internal System of Units (SI) in organic analysis. The capability of quantitative analysis is recognized as the beginning of NMR development. NMR signals are proportional to the number of nuclei and qNMR has been used in various fields, such as metabolomics and food and pharmaceutical analysis. However, careful sample preparation and thorough optimization of measurement parameters are required to obtain accurate and reliable results. In this review, quantitative methods used in qNMR are discussed, and the important factors to be considered also introduced. The recent development of qNMR techniques including combination with chromatography and, multidimensional NMR are also presented.

Complete Assignment of $^{1}H$ and $^{13}C$-NMR Signals for (20S) and (20R)-Protopanaxadiol by 2D-NMR Techniques (2D-NMR 기법을 이용한 (20S)와 (20R)-Protopanaxadiol의 $^{1}H$- 및 $^{13}C$-NMR 완전 동정)

  • 백남인;김동선
    • Journal of Ginseng Research
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    • v.19 no.1
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    • pp.45-50
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    • 1995
  • (20S)- and (20R)-protopanaxadiol were prepared from crude ginseng saponin by chemical treatment. The $^{1}H$- and $^{13}C$-NMR signals of these compounds were fully assigned by various NMR techniques such as DEPT, 1H-1H COSY, HMQC, HMBC and NOESY.

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Practical Guide to NMR-based Metabolomics - III : NMR Spectrum Processing and Multivariate Analysis

  • Jung, Young-Sang
    • Journal of the Korean Magnetic Resonance Society
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    • v.22 no.3
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    • pp.46-53
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    • 2018
  • NMR-based metabolomics needs various knowledge to elucidate metabolic perturbation such as NMR experiments, NMR spectrum processing, raw data processing, metabolite identification, statistical analysis, and metabolic pathway analysis regarding technical aspects. Among them, some concepts of raw data processing and multivariate analysis are not easy to understand but are important to correctly interpret metabolic profile. This article introduces NMR spectrum processing, raw data processing, and multivariate analysis.

Structural characteristics of [N(CH3)4]2CdCl4 determined by 1H MAS NMR, 13C CP/ MAS NMR, and 14N NMR

  • Lee, Seung Jin;Lim, Ae Ran
    • Journal of the Korean Magnetic Resonance Society
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    • v.19 no.1
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    • pp.18-22
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    • 2015
  • The structural geometry of $[N(CH_3)_4]_2CdCl_4$ in a hexagonal phase is studied by $^1H$ MAS NMR, $^{13}C$ CP/MAS NMR, and $^{14}N$ NMR. The changes in the chemical shifts for $^{13}C$ and $^{14}N$ in the hexagonal phase are explained by the structural geometry. In addition, the temperature dependencies of the spin-lattice relaxation time in the rotating frame $T_{1{\rho}}$ for $^1H$ MAS NMR and $^{13}C$ CP/MAS NMR are measured.

Nanoscale-NMR with Nitrogen Vacancy center spins in diamond

  • Lee, Junghyun
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.2
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    • pp.59-65
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    • 2020
  • Nitrogen-Vacancy (NV) center in diamond has been an emerging versatile tool for quantum sensing applications. Amongst various applications, nano-scale nuclear magnetic resonance (NMR) using a single or ensemble NV centers has demonstrated promising results, opening possibility of a single molecule NMR for its chemical structural studies or multi-nuclear spin spectroscopy for quantum information science. However, there is a key challenge, which limited the spectral resolution of NMR detection using NV centers; the interrogation duration for NV-NMR detection technique has been limited by the NV sensor spin lifetime (T1 ~ 3ms), which is orders of magnitude shorter than the coherence times of nuclear spins in bulk liquid samples (T2 ~ 1s) or intrinsic 13C nuclear spins in diamond. Recent studies have shown that quantum memory technique or synchronized readout detection technique can further narrow down the spectral linewidth of NMR signal. In this short review paper, we overview basic concepts of nanoscale NMR using NV centers, and introduce further developments in high spectral resolution NV NMR studies.

On the Structure and the Extent of Disorder in Non-crystalline Silicates at High Pressure: 2 Dimensional Solid-state NMR Study (2차원 고상 핵자기 공명기를 이용한 비정질 규산염의 고압구조 및 무질서도에 대하여)

  • Lee Sung Keun
    • Journal of the Mineralogical Society of Korea
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    • v.18 no.1
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    • pp.45-52
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    • 2005
  • The recent development and advances in 2 dimensional solid-state NMR, particularly, triple quantum (3Q) MAS NMR yield much improved resolution compared with conventional 1 dimensional MAS NMR, allowing us to study the distributions of cations and anions in the non-crystalline silicate glasses and melts. Here, we present the recent progress made by 3QMAS NMR spectra of silicate glasses quenched from melts at pressures up to 10 GPa in a multi-anvil apparatus, revealing previously unknown details of structures of covalent oxide glasses and melts at high pressure.

The Simulation of MAS-NMR Spectrum by the Voight Lineshape (Voight 함수를 이용한 MAS-NMR 스펙트럼 시뮬레이션)

  • Kang, Myoung Jin;Shim, Moon Sik;Ryu, Yung Rae
    • Journal of Korean Ophthalmic Optics Society
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    • v.2 no.1
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    • pp.17-24
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    • 1997
  • The Voight function which results from the convolution of the Gauss and Lorentz function is applied the MAS-NMR simulation of mixed alkali glasses and the glasses doped transition metal oxides. It is well known that the convolution of the Gauss and Lorentz function cannot be integrated in closed form for arbitrary values. So we make the new computer simulation program from which the Voight lineshape is obtained. The results are accorded well with the MAS-NMR spectra and we can find out the very small change of MAS-NMR lineshape.

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Recent NMR developments for pharmaceutical research

  • Lee, Kwanghwan
    • Journal of the Korean Magnetic Resonance Society
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    • v.20 no.1
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    • pp.27-35
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    • 2016
  • NMR spectrometer has been regarded as essential tool for structure elucidation in variable scientific field as like organic synthesis, natural product and macro protein research. Also NMR can be applied for defining dynamic behavior like ligand and receptor binding. One of advantage of research with NMR is that to be great confident to confirm structure and the measured sample could be recovered. Nevertheless NMR also has a weak points than other spectroscopic methods that require a lot of time for interpreting acquired spectrum and running time due to low sensitivity. For last two decade Bruker has developed hardware and software solution for overcome those weak points. In order to overcome low sensitivity Bruker introduced Cryo and Micro diameter probe head technology. And researcher can reduce the time for routine spectrum processing and interpretation works due to lots of introductions in software solutions for quantification, identification and statistics analysis. With four examples, this article describing those new hardware and software solutions in field of recent pharmaceutical research as follows. - New Horizons for NMR in the Biopharmaceutical Industry - The development and application of solid-state NMR spectroscopy (SSNMR) in pharmaceutical analysis - Assisted NMR Data Interpretation in Synthetic Chemistry - Complete Analysis of New Psychoactive Substances Using NMR.