Low-power suppression of fast-motion spin 3/2 signals.
Triple Quantum Filters (TQFs) are frequently used for the selection of bi-exponentially relaxing spin 3/2 nuclei (in particular23Na) in ordered environments, such as biological tissues. These methods provide an excellent selection of slow-motion spins, but their sensitivity is generally low, and coherence selection requirements may lead to long experiments when applied in vivo. Alternative methods, such as 2P DIM, have demonstrated that the sensitivities of the signals from bi-exponentially relaxing sodium can be significantly increased using strategies other than TQFs. A shortcoming of the 2P DIM method is its strong dependence on B0inhomogeneities. We describe here a method, which is sensitive to the slow-motion regime, while the signal from spins in the fast-motion regime is suppressed. This method is shown to be more effective than TQFs, requires minimal phase cycling for the suppression of the influence of rf inhomogeneity, and has less dependence on resonance offsets and B0-inhomogeneity than 2P DIM.
Department of Chemistry, New York University, New York, NY 10003, USA.
Evgeny
E
Nimerovsky
Department of Chemistry, New York University, New York, NY 10003, USA.
Andrew J
AJ
Ilott
Department of Chemistry, New York University, New York, NY 10003, USA. Electronic address: alexej.jerschow@nyu.edu.
Alexej
A
Jerschow
D009682:Magnetic Resonance Spectroscopy; D012964:Sodium
D012964:Sodium
Bi-exponential relaxation; Slow-motion sodium; Sodium NMR; Weak radio-frequency fields