Nuclear magnetic resonance instruments

B5. Bible, R. H., Nuclear magnetic resonance instrumentation since the Varian A-60. Appl. Spectrosc. 24, 326-331 (1970). 

In 1987 Gahler and Golub suggested a new type of spectroineter designed as "neutron resonance spin echo" or on "zero field neutron spin echo" that uses radiofrequency coils directly inspired from nuclear magnetic resonance.Instruments of this type have been built at HMI and LLB or are under development (Munich). 

ELECTRON PARAMAGNETIC RESONANCE NUCLEAR MAGNETIC resonance). Instruments for obtaining spectra of particle beams are also called spectrometers (see spectrum photo-electron spectroscopy). 

As was true with infrared and nuclear magnetic resonance instruments. Fourier transform mass spectrometers provide improved signal-to-noisc ratios, greater speed, and higher sensitivity and resolution." Commercial Fourier transform mass spectrometers appeared on the market in the early 1980s and are now offered by several manufacturers. 

The second category of human capacity enhancement is augmentation. Augmentation is well exemplified with nuclear magnetic resonance instruments. There is no a-priori human ability to detect the resonance of nuclear magnetic moments to an external magnetic field. NMR equipment gives humans instrumental access to physical phenomena beyond our unaided capacities. 

To find explosives Gas analyzers, chromatography instruments, drift-spectrometers, neutron defectosopes, nuclear-magnetic and nuclear-quadrupole resonant instruments... 

Specinfo, from Chemical Concepts, is a factual database information system for spectroscopic data with more than 660000 digital spectra of 150000 associated structures [24], The database covers nuclear magnetic resonance spectra ( H-, C-, N-, O-, F-, P-NMR), infrared spectra (IR), and mass spectra (MS). In addition, experimental conditions (instrument, solvent, temperature), coupling constants, relaxation time, and bibliographic data are included. The data is cross-linked to CAS Registry, Beilstein, and NUMERIGUIDE. 

Present day techniques for structure determination in carbohydrate chemistry are sub stantially the same as those for any other type of compound The full range of modern instrumental methods including mass spectrometry and infrared and nuclear magnetic resonance spectroscopy is brought to bear on the problem If the unknown substance is crystalline X ray diffraction can provide precise structural information that m the best cases IS equivalent to taking a three dimensional photograph of the molecule... 

The modern electronic industry has played a very important role in the development of instrumentation based on physical-analytical methods As a result, a rapid boom in the fields of infrared, nuclear magnetic resonance (NMR), Raman, and mass spectroscopy and vapor-phase (or gas-liquid) chromatography has been observed. Instruments for these methods have become indispensable tools in the analytical treatment of fluonnated mixtures, complexes, and compounds The detailed applications of the instrumentation are covered later in this chapter. 

Bovey, F A, Jelmski, L, Mirau, P A Nuclear Magnetic Resonance Spectroscopy, 2nd ed, Acadermc Press New York, 1988 Proton and Fluorine Nuclear Magnetic Resonance Spectral Data, Vanan Instruments/Japan Halon Tokyo, 1988... 

Some preliminary laboratory work is in order, if the information is not otherwise known. First, we ask what the time scale of the reaction is surely our approach will be different if the reaction reaches completion in 10 ms, 10 s, 10 min, or 10 h. Then, one must consider what quantitative analytical techniques can be used to monitor it progress. Sometimes individual samples, either withdrawn aliquots or individual ampoules, are taken. More often a nondestructive analysis is performed, the progress of the reaction being monitored continuously or intermittently by a technique such as ultraviolet-visible spectrophotometry or nuclear magnetic resonance. The fact that both reactants and products might contribute to the instrument reading will not prove to be a problem, as explained in the next chapter. 

Flexible superconducting tapes provide promise of uses for superconductors in motors, generators, and even electric transmission lines. Meanwhile, superconducting magnets cooled to the temperature of liquid helium already are in use. High-field nuclear magnetic resonance (NMR) spectrometers have become standard instruments in chemical research laboratories, and the same type of machine (called an MRI spectrometer) is used for medical diagnosis in hospitals worldwide. 

Electrochemical nuclear magnetic resonance (NMR) is a relatively new technique that has recently been reviewed (Babu et al., 2003). NMR has low sensitivity, and a typical high-held NMR instrument needs 10 to 10 NMR active atoms (e.g., spins), to collect good data in a reasonable time period. Since 1 cm of a single-crystal metal contains about 10 atoms, at least 1 m of surface area is needed to meet the NMR sensitivity requirement. This can be met by working with carbon-supported platinum... 

Local Structure of the Eu2+ Impurity. From the experimental perspective, the doping of lanthanide ions into solid state materials can be probed by different instrumental technics such as nuclear magnetic resonance (NMR),44 extended X-ray absorption fine structure (EXAFS),45,46 or electron paramagnetic resonance (EPR),47 which instead of giving a direct clue of the local geometry offers only data that can be corroborated to it. From the theoretical point of view,... 

Proton and carbon-13 nuclear magnetic resonance (NMR) spectra were recorded on a IBM Instruments 270 MHz NMR Spectrometer on 6-8 weight percent solutions in deuterated chloroform. Ultraviolet spectra were recorded on an IBM Ultraviolet Spectropluitometer Model 9420 using chloroform solutions containing 2 x 10-5 g/ml of the copolymers. 

If one wishes to obtain a fluorine NMR spectrum, one must of course first have access to a spectrometer with a probe that will allow observation of fluorine nuclei. Fortunately, most modern high field NMR spectrometers that are available in industrial and academic research laboratories today have this capability. Probably the most common NMR spectrometers in use today for taking routine NMR spectra are 300 MHz instruments, which measure proton spectra at 300 MHz, carbon spectra at 75.5 MHz and fluorine spectra at 282 MHz. Before obtaining and attempting to interpret fluorine NMR spectra, it would be advisable to become familiar with some of the fundamental concepts related to fluorine chemical shifts and spin-spin coupling constants that are presented in this book. There is also a very nice introduction to fluorine NMR by W. S. and M. L. Brey in the Encyclopedia of Nuclear Magnetic Resonance.1... 

Several modem analytical instruments are powerful tools for the characterisation of end groups. Molecular spectroscopic techniques are commonly employed for this purpose. Nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and mass spectrometry (MS), often in combination, can be used to elucidate the end group structures for many polymer systems more traditional chemical methods, such as titration, are still in wide use, but employed more for specific applications, for example, determining acid end group levels. Nowadays, NMR spectroscopy is usually the first technique employed, providing the polymer system is soluble in organic solvents, as quantification of the levels of... 

The proton nuclear magnetic resonance (NMR) spectra of primaquine diphosphate was obtained using a Bruker instrument operating at 300, 400, or 500 MHz. 

---