Cereal Chem 66:244-246   |  VIEW ARTICLE

Note: Contribution of Proton Exchange to the Oxygen-17 Nuclear Magnetic Resonance Transverse Relaxation Rate in Water and Starch-Water Systems.

S. J. Richardson. Copyright 1989 by the American Association of Cereal Chemists, Inc. 

The contribution of proton exchange to the oxygen-17 nuclear magnetic resonance (NMR) transverse relaxation rate (R2/sec) in water and corn starch-water systems as a function of pH was investigated. Proton exchange broadening was observed for both systems to be maximal at neutral pH. Two methods of decreasing or eliminating the broadening were also investigated: use of D2O as a solvent and use of proton decoupling in the 17O NMR R2 experiments. The use of proton decoupling efficiently reduces the broadening effects and thus is the recommended method when investigating water mobility by 17O NMR.