Water signal suppression

Ti of water in the body ranges from 400 ms to 3 s and no single TI value leads to complete water signal suppression everywhere. 

Some methods take advantage of a difference in a particular property between water and the molecule to be studied. In particular, a macromolecule usually has a shorter value for proton Tt than water and a much lower diffusion coefficient. One of the oldest methods for water signal suppression is WEFT (water elimination Fourier transform), in which an inversion recovery sequence is applied (see Fig. 2.12) with r chosen to be the time that the water signal goes through zero (Tj In 2), just as in the BIRD pulse sequence. Another method makes use of the technique described in Section 9.3 to measure diffusion coefficients. 

WATER SIGNAL SUPPRESSION IN NMR SPECTROSCOPY 309 3.4. Magnetization destruction>based mediods... 

The first chapter by J. C Lindon, J. K. Nicholson and J. R. Everett covers the NMR Spectroscopy of Biofluids. This is followed by an account of Studies of Biological Ion Transporting Channels from J. E Hinton. The third chapter by D. Gudat relates to Applications of Heteronuclear X,Y-correlation Spectroscopy in OrganometalUc and Organoelement Chemistry. B. Wrack-meyer reports on Applications of Sn NMR Parameters. Cu NMR Spectroscopy is the area covered in the chapter by J. Malito. The penultimate account is by W. S. Price on Water Signal Suppression in NMR Spectroscopy. In the final chapter, T. Baba and Y. Ono discuss Variable Temperature MAS NMR A Powerful Tool for the Investigation of Dynamic Properties of Acidic Protons in Zeolites and Heteropoly Compounds. 

Nuclear magnetic resonance (NMR) spectroscopy has proven to be the most versatile technique to study organometallic compounds both non-aqueous and aqueous solutions [6, 7]. To explore all the possibilities of NMR one has to either work in DzO as solvent or use a water signal suppression technique. Proton chemical shifts can give information about the structure. Generally, protons bound to carbons coordinated to a metal center show a low-field shift, about 1-4 ppm, compared with the metal-free environment. Metal hydrides usually have negative... 

Load the configuration file ch5239.cfg and simulate the 1H spectrum without water signal suppression (Go I Run experiment). Process the FID using zero... 

Gueron M and Plateau P (1996) Water signal suppression in NMR of biomolecules. In Grant DM and Harris RK (eds). Encyclopedia of Nuclear Magnetic Resonance, pp 4931-4942. Chichester Wiley. 

Upon analysis 720 (il of perchloric extract were added 80 (il of D2O and pH was adjusted to 7.80. Subsequently, the samples were centrifuged 5 min at 14,000 rpm at room temperature and the clear supernatant placed into 5-mm NMR tubes. NMR spectra were acquired at 298 K using a Varian Mercury 400 MHz NMR spectrometer. The flip angle pulse was chosen to be 60° and the standard Varian presat pulse sequence was applied to allow efficient water signal suppression. 

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