Suppression of phase and amplitude J(HH) modulations in HSQC experiments

• Published in: Magnetic resonance in chemistry 2015-02, Vol.53 (2), p.115-119
• Main Authors: Castañar, Laura, Sistaré, Eduard, Virgili, Albert, Williamson, R. Thomas, Parella, Teodor
• Format: Article
• Language: English
• Subjects: Amplitudes; Constants; Delay; HSQC; J(HH) modulation; Joining; NMR; Optimization; perfect HSQC; pure in-phase signals; Simulation; Spectra; Two dimensional
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.4149

The amplitude and the phase of cross peaks in conventional 2D HSQC experiments are modulated by both proton–proton, J(HH), and proton–carbon, 1J(CH), coupling constants. It is shown by spectral simulation and experimentally that J(HH) interferences are suppressed in a novel perfect‐HSQC pulse scheme that incorporates perfect‐echo INEPT periods. The improved 2D spectra afford pure in‐phase cross peaks with respect to 1J(CH) and J(HH), irrespective of the experiment delay optimization. In addition, peak volumes are not attenuated by the influence of J(HH), rendering practical issues such as phase correction, multiplet analysis, and signal integration more appropriate. Copyright © 2014 John Wiley & Sons, Ltd. The amplitude and the phase of cross‐peaks in conventional 2D HSQC experiments are modulated by both proton–proton, J(HH), and proton–carbon, 1J(CH), coupling constants. It is shown by spectral simulation and experimentally that J(HH) interferences are suppressed in a novel perfect‐HSQC pulse scheme that incorporates perfect‐echo INEPT periods. The improved spectra afford pure in‐phase cross‐peaks with respect to 1J(CH) and J(HH), irrespective of the experiment delay optimization, providing better analysis in terms of J measurement or signal integration.