Abstract: In this paper, the theoretical principle, the influential effect on T₂ of the water proton and application of a WATR method are discussed.
The method involves adding water proton exchange reagents, e. g.ammonium chloride, hydroxylamine hydro-chloride and guanidinium, into aqueous solutions to reduce T₂ of the water proton and then measuring ¹H-NMR spectra by CPMG pulse sequence.
The resonance of samples especially at or near the frequency of the water resonance in dilute aqueous solutions was clearly observable. The chemical shifts and coupling constants of ¹⁵N-¹H in dilute aqueous solutions were also observable, which up to now has never been reported about this aspect.

Key words: dilute aqueous solutious, proton exchange reagents, CPMG pulse sequence, ¹H-NMR