Simultaneous Multi‐Slice Excitation in Spatially Encoded NMR Experiments

Abstract

Improved sensitivity: A novel strategy to enhance the experimental sensitivity in spatially encoded NMR experiments has been developed. The use of a multiple-frequency modulated pulse applied simultaneously to an encoding gradient can afford a substantial sensitivity gain with respect to single-slice selected experiments.

1D NMR Homodecoupled 1H Spectra with Scalar Coupling Constants from 2D NemoZS‐DIAG Experiments

“…Applications using 10-50 irradiations worked quite well on the carbon spectra of 13 Cenriched compounds,b ut the probability of accidental selection of pairs of coupled spins is much higher in 1 HNMR spectroscopy and resulted to artifacts (see Figure S3). One solution would consists in avoiding this situation and generating lists of frequencies tailored to as pecific sample, [12] but we preferred to face the problem in the perspective of ag enerally applicable method. We therefore introduce here an alternative scheme of modulation of the selective pulse where the modulation sites are non-equidistant.…”

“…Signal assignment was clearly facilitated by the availability of the coupling constants.K nowing that all couplings above 9Hzare geminal (12)(13)(14)(15)(16)(17)(18)(19)(20) Hz in the case of androsten) or trans diaxial (9)(10)(11)(12)(13)(14)(15), the visual inspection of the couplings …”

Real‐Time Band‐Selective Homonuclear Proton Decoupling for Improving Sensitivity and Resolution in Phase‐Sensitive J‐Resolved Spectroscopy

“…In particular,the real-time band-selectivehomonuclear (BASH)d ecoupling, although not broadband,i mproves both the resolution as well as the sensitivity of 1D 1 HNMR spectroscopy and in the direct dimensions of various 1 H-detected 2D NMR spectroscopy [27,36,41] in ab and-or spin-selectivem anner. Recently,aband-selective 'pure-shift' selectiver efocusing (SERF)t echnique was proposed to extract 1 H-1 H J coupling between selected 1 Hp airs in overcrowdeds pectral regions.…”

“…[27,36,41].T he nonselective 908 pulse after the z filter in Figure 1A,i sr eplaced by aE Burp-2 shaped 908 pulse marked as Ei nF igure 1B for the selective excitation of the group of resonances in the real-time BASH-decoupled J-resolved experiment.H ollow-shaped pulses marked as rw ere appliedp eriodically during acquisition anda re 1808 ReBurp shaped pulses for refocusing the protons of interest, they were followed by an onselective 1808 pulse to invert all spins. As ar esult, the protons of interestw ere selectively decoupled from the rest, while allowing their chemical-shift evolution to continue during acquisition.…”

“…[27,36,41] The proton-proton decoupling is achieved by repeated application of ab and-selective and an onselective 1808 pulse pair during interrupted acquisition. Peptides and proteins are suitable for the BASH/HOBS method as they offer the unique opportunity forb and-selective refocusing of amide protons ( 1 H N )o ra lpha protons ( 1 H a ).…”