Solvent suppression in liquid state NMR with selective intermolecular zero-quantum coherences

Abstract

We compared several variants of 2D selective intermolecular zero-quantum pulse sequences which use selective pulses and selective refocusing modules in different positions within the sequence to achieve suppression of the solvent signal. We show that a theoretical two-fold gain in cross peak intensity in the selective spectra, compared to the non-selective sequence, is only valid for certain parameters and is additionally influenced by faster signal build-up and better solvent suppression. We show experimentally that for low concentration solutes application of a single selective mixing pulse suppresses solvent signal efficiently. Further selective refocusing modules can actually reduce this efficiency.