Water flip-back

From NMR Wiki

In water flip-back element a hard readout 90^o pulse on ¹H is preceded by a selective 90^o pulse on water resonance with phase opposite to that of the hard pulse.

If ¹H magnetization was along z axis before the selective pulse, water resonance will stay along z and won't be observed.

References

1. Grzesiek, S and Bax, A. The importance of not saturating water in protein NMR. Application to sensitivity enhancement and NOE measurements. Journal of the American Chemical Society 115(26):12593--12594, 1993. BibTeX [wfb]