Flow injection analysis NMR (FIA–NMR): a novel flow NMR technique that complements LC–NMR and direct injection NMR (DI–NMR)

Details of a new flow NMR technique, flow injection analysis NMR (FIA–NMR), are presented for the first time. This method blends some aspects of both liquid chromatography–NMR and direct injection NMR, and complements both. FIA‐NMR is shown to be useful as an analytical technique, especially for repetitive analyses, and may also prove useful in the analysis of combinatorial chemistry libraries. The feasibility of FIA‐NMR is demonstrated by the quantitative analysis of an over‐the‐counter pharmaceutical. Copyright © 2003 John Wiley & Sons, Ltd.     

Thallium NMR spectroscopy

Nuclear magnetic resonance spectroscopy has proven to be a powerful technique for solving a wide variety of problems. However, the full potential of the technique as extended to the study, through direct observation, of heavy metals in both the solid and solution state is just beginning to be realized.     

Gas-Phase NMR Spectroscopy

The Murnaghan-Hildebrand equation of state, an accurate equation of state for many solids and liquids, is introduced for use in the illustration of thermodynamic relationships. It is shown to meet the need for an equation of state accurate over a wide range of pressures. Parameters are given for four solid phases of iron and for the liquid, with which eleven thermodynamic functions including V, U, H, S, V, V/B, and G can be calculated at any specified temperature and pressure. The program for these calculations can be used to represent experimental values, to illustrate thermodynamic relationships, to calculate chemical and phase equilibria, and to stimulate student interest from the study of real systems, for instance, the form of iron in the core of the earth.     

Hyperdimensional NMR spectroscopy

Hyperdimensional NMR describes the multiple interactions between a large number, N, of coupled nuclear spins. We show how to construct a hypothetical N-dimensional spectrum from a limited set of low-dimensional measurements, exploiting the concept of projection-reconstruction. In the process, many correlation spectra are obtained that were not investigated directly. As an illustration, the hypothetical ten-dimensional spectrum of a small protein (agitoxin) has been reconstructed, and a large number of pairwise correlation spectra have been recorded.     

NMR on polyelectrolytes

Nuclear magnetic resonance (NMR) is a versatile tool for the investigation of structure and molecular mobility in soft mater. It is a standard technique for structure determination of polymers and polyelectrolytes. In addition NMR provides information on both the polyelectrolyte, the counterions and often valuable information originating from the surrounding medium. High-resolution NMR spectroscopy enables the observation of counterion interaction in particular π interactions as well as the information about spatial proximity of functional groups in polyelectrolyte complexes. Combinations of PFG NMR and electrophoresis NMR permit the direct observation of counterion condensation. Cryoporometry showed different states of water interacting with polyelectrolytes in multilayers. Solid-state NMR has been applied to investigate both packing effects and local molecular dynamics in polyelectrolyte multilayers. The current research in the field is reviewed.     

Rotenone NMR assignments

Complete and unambiguous ¹³C nmr assignments for rotenone have been determined and are presented along with proton nmr data.     

Heteronuclear zero-field NMR

The NMR spectra of polycrystalline solids are often best resolved in the absence of applied magnetic fields. Additionally, heteronuclear spin systems in zero field display features not observed in homonuclear systems. In this letter, spectra are presented and analyzed for the cases of heteronuclear spin pairs in ¹³C-enriched β-calcium formate (solid) and in diethyl phosphite (liquid).     

2D NMR对Sarcophine所有^1H NMR和^1^3C NMR归属的指定

从中国南海软珊瑚Sarcophyton molle中分离得到大环二萜内酯Sarcophine(1)。本文利用^1H-^1H COSY，HMQC，HMBC等二维谱手段首次对Sarcophine所有^1H NMR、^1^3C NMR的信号归属进行了完全的指定。并第一次报道了其^1^3C NMR数据。     

NMR studies of enzymes

Summary Studies of enzymes have been greatly assisted by advances in NMR methods in recent years. The main advances have been in magnetic fields (both very high strengths and very large volumes of homogeneous field are now available), in improved sensitivity, and in advances in data handling and radio-frequency pulse generation. NMR studies of enzymes have been valuable in complementing information obtained from other methods in a variety of ways but in this review two areas where developments have been particularly rapid in recent years will be discussed. These are: high resolution studies of purified proteins and studies of metabolites in intact cells. The valuable information which can be extracted in these two respective areas can be summarised as: a) structural, energetic and dynamic information about specific groups on the enzyme and its ligands in solution and b) detailed comparisons of the properties of the enzyme expressed when it is in a purified form (in vitro) and when it is in the intact cell (in vivo). Some ways in which recent advances in NMR technology have affected these two rather different approaches to enzyme studies will be illustrated with specific examples.

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NMR-Untersuchungen von Enzymen

Zusammenfassung Durch die Weiterentwicklung der NMR-Technik wurde in den letzten Jahren die Untersuchung von Enzymen stark gefördert. Die hierfür wesentlichen Fortschritte wurden beim Magnetfeld (sowohl sehr hohe Feldstärken als auch große Volumina mit homogenem Magnetfeld sind jetzt verfügbar), bei der Empfindlichkeit, bei der Datenverarbeitung und bei der Erzeugung von Radiofrequenz-Pulsen erreicht. Enzymuntersuchungen mit der NMR-Spektroskopie ergänzen die Informationen, die mit anderen Methoden erhalten wurden, in vielfacher Hinsicht.In diesem Überblick werden vor allem zwei Bereiche behandelt, die sich in den letzten Jahren besonders schnell entwickelt haben; nämlich hochauflösende Untersuchungen von gereinigten Proteinen und Untersuchungen der Metabolite in intakten Zellen. Die in diesen Bereichen erhältlichen Ergebnisse können zusammengefaßt werden zu a) Informationen über Struktur, Energie und Dynamik spezifischer Gruppen der Enzyme und seiner Liganden in Lösung und b) detaillierten Vergleichen der Enzyme in gereinigter Form (in vitro) und in der intakten Zelle (in vivo). Spezifische Beispiele für die Bedeutung einiger Fortschritte der NMR-Technik für diese relativ unterschiedlichen Ansätze werden gegeben.