High-resolution intermolecular zero-quantum coherence spectroscopy under inhomogeneous fields with effective solvent suppression

Abstract

Intermolecular zero-quantum coherences (iZQCs) are not susceptible to magnetic field inhomogeneities significantly larger than the dipolar correlation distance and can be used to obtain 1D high-resolution spectra in an inhomogeneous field. However, with the iZQC methods proposed previously, residual conventional single-quantum coherences (SQCs) originating mainly from solvent resonance result in strong t₁ ridge noises. A modified HOMOGENIZED with an intermolecular double-quantum filter (iDQF), named iDQF-HOMOGENIZED, is presented in this work to suppress the residual conventional SQC signals as well as solvent iZQC signals. The solvent-suppression efficiency of the iDQF-HOMOGENIZED is analyzed and a thorough comparison of the new sequence with several relevant pulse sequences is made. Dramatic resolution enhancement and solvent suppression in the measurements of a piece of grape sarcocarp suggest potential applications of the method in in vivo spectroscopy.