Nuclear analytical techniques structure

In some nuclear analytical techniques there are specific interactions (coupling) between the energy levels of electrons and nuclei. Although such interactions are rather weak, they may occasionally provide interesting possibilities to give information on electronic and molecular structures. This is the case for analysis via the Mossbauer effect and via NMR. However, it should be noted that only a part of the nucleus is suited for NMR, and the Mossbauer effect can only be applied to a rather small number of nuclei." ... 

Nuclear Analytical Techniques for the Structural Analysis of Metallomes and Metalloproteomes... 

Analysis of a metallodrug in a biological tissue is a challenging task in analytical chemistry, primarily because the traditional methods used are usually indirect and semi-quantitative to a large extent, and are unable to visualize the metal ions in vivo. Advanced nuclear analytical techniques, such as X-ray fluorescence, neutron activation analysis. X-ray emission. X-ray absorption near-edge structure spectroscopy, nuclear magnetic resonance, and isotope tracing/dilution techniques offer some means by which elemental distribution, oxidation states, and species structural information can be studied. ... 

Corresponding to the objects of elementomics study, different analytieal techniques can be used to reach these goals. The applieation of advaneed nuclear analytical techniques on metalloproteomies study has been reviewed by Gao et alP In the following parts, nuelear analytieal teehniques, whieh ean achieve some of the above goals of nanometallomies, espeeially analytieal techniques for characterization, elemental quantifieation and distribution, and structural analysis of metallic nanomaterials, will be introdueed. 

Yuxi Gao is an associate professor at Institute of High Energy Physics, Chinese Academy of Sciences. He obtained his PhD degree in environmental sciences in 2000 from Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. His current research focuses on the methodology of metallomics and metallo-proteomics based on the nuclear analytical techniques the applications of metallomics and metalloproteomics tourniquets on the environmental and biomedical research the homeostasis of trace elements and their regulatory mechanism the structure, function and structure-function relationship of important metalloproteins. 

NMR, nuclear magnetic resonance, is an analytical technique based on the energy differences of nuclear spin systems in a strong magnetic field. It is a powerful technique for structural elucidation of complex molecules. 

Mass spectrometry is an analytical technique to measure molecular masses and to elucidate the structure of molecules by recording the products of their ionization. The mass spectrum is a unique characteristic of a compound. In general it contains information on the molecular mass of an analyte and the masses of its structural fragments. An ion with the heaviest mass in the spectrum is called a molecular ion and represents the molecular mass of the analyte. Because atomic and molecular masses are simple and well-known parameters, a mass spectrum is much easier to understand and interpret than nuclear magnetic resonance (NMR), infrared (IR), ultraviolet (UV), or other types of spectra obtained with various physicochemical methods. Mass spectra are represented in graphic or table format (Fig. 5.1). 

Hyphenated analytical techniques such as LC-MS, which combines liquid chromatography and mass spectrometry, are well-developed laboratory tools that are widely used in the pharmaceutical industry. Eor some compounds, mass spectrometry alone is insufficient for complete structural elucidation of unknown compounds nuclear magnetic resonance spectroscopy (NMR) can help elucidate the structure of these compounds (see Chapter 20). Traditionally, NMR experiments are performed on more or less pure samples, in which the signals of a single component dominate. Therefore, the structural analysis of individual components of complex mixtures is normally time-consuming and less cost-effective. The... 

Until quite recently, X-ray crystallography was the technique used almost exclusively to resolve the 3-D structure of proteins. As well as itself being technically challenging, a major limitation of X-ray crystallography is the requirement for the target protein in crystalline form. It has thus far proved difficult or impossible to induce the majority of proteins to crystallize. Nuclear magnetic resonance (NMR) is an analytical technique which can also be used to determine the three-dimensional structure of a molecule without the necessity for crystallization. For many years, even the most powerful NMR machines could resolve the 3-D structure of only relatively small proteins (less than 20-25 kDa). However, recent analytical advances now render it possible to successfully analyse much larger proteins by this technique. 

Nuclear magnetic resonance (NMR) spectroscopy is a powerful and versatile analytical technique that can provide site-specific information about chemical bonding, structure and dynamics in molecular systems. NMR applications have made a major impact in a variety of disciplines ranging from materials science to molecular biology and bioinorganic... 

FTMS also has the potential of becoming an important tool for determining molecular structure. Traditionally, mass spectrometry has been rather limited in its ability to determine the structure of an unknown compound unambiguously. Additional structural methods, such as nuclear magnetic resonance or crystallography, are commonly used in conjunction with mass spectrometry to elucidate the identity of a molecule. However, when the amount of sample is severely limited or when the sample is a component in a complex mixture, mass spectrometry is often one of the few analytical techniques that can be used. 

Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most powerful analytical techniques in organic chemistry for elucidating the molecular structures of chemicals (1,2). Moreover, an NMR spectrum may be used like a fingerprint to identify a chemical by comparing it with its reference spectrum recorded from the authentic chemical under comparable conditions. The spectrum also reveals information on molecular conformation, isomerism, molecular dynamics, and diastereomers (3 6). 

Infrared spectroscopy (IR) is one of the oldest instrumental analytical techniques but its value in structural analysis has decreased with the rise of nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Compared to the traditional dispersive IR techniques, Fourier transform infrared spectroscopy (FTIR) offers more sampling techniques. 

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