title: The use of a selective saturation pulse to suppress t1 noise in two-dimensional (1)H fast magic angle spinning solid-state NMR spectroscopy.
abstract: A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+kHz) suppresses t1 noise in the indirect dimension of two-dimensional (1)H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl (1)H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion--this is quantified by comparing two-dimensional (1)H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear (1)H-(1)H double quantum (DQ)/single quantum (SQ) MAS and (14)N-(1)H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom; Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Aiden J
authors.initials: AJ
authors.lastname: Robertson
authors.affiliation: RIKEN CLST-JEOL Collaboration Centre, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Pandey
authors.affiliation: Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Marsh
authors.affiliation: RIKEN CLST-JEOL Collaboration Centre, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nishiyama
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom. Electronic address: S.P.Brown@warwick.ac.uk.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Brown
mesh_terms: D000465:Algorithms; D003562:Cytidine / Q000031:analogs & derivatives / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D008745:Methylation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D017646:Organosilicon Compounds / Q000737:chemistry
chemical_list: D017646:Organosilicon Compounds; D003562:Cytidine; D004247:DNA
keywords: (1)H two-dimensional solid-state NMR; DNA based analogue; Fast MAS; Selective saturation pulse; t(1) noise