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Proton NMR spectroscopy of solvent‐saturable resonances: A new approach to study pH effects in Situ
Author(s) -
Mori Susumu,
Eleff Scott M.,
Pilatus Ulrich,
Mori Noriko,
van Zijl Peter C. M.
Publication year - 1998
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910400105
Subject(s) - proton , chemistry , nuclear magnetic resonance , solvent , nuclear magnetic resonance spectroscopy , saturation (graph theory) , analytical chemistry (journal) , spectroscopy , magnetization transfer , proton nmr , ph indicator , chromatography , magnetic resonance imaging , stereochemistry , physics , organic chemistry , nuclear physics , medicine , mathematics , combinatorics , quantum mechanics , radiology
It is shown that the effect of pH changes can be measured in proton NMR spectra through the pH sensitivity of the signal intensities of metabolite protons exchanging with water. To observe this phenomenon, pulse sequences must be used that can sensitively observe these exchangeable protons under physiological conditions, which is achieved by avoiding magnetization transfer signal losses due to water saturation for solvent suppression purposes. These methods provide an order‐of‐magnitude enhancement of many signals between 5 and 10 ppm, containing both N‐bound protons as well as aromatic C‐H protons coupled to them, the intensity of which is influenced by exchange‐relayed saturation. As a first application, the effects of pH change on these resonances are studied ex vivo (perfused cells) and in vivo (cat brain).