Hadamard encoded 2D correlation spectroscopy in inhomogeneous fields

In this Letter, we present a new approach to obtain two-dimensional high-resolution COSY spectra in inhomogeneous fields based on Hadamard encoding. It is an extension of one-dimensional high-resolution intermolecular double-quantum coherence Hadamard encoding approach. The approach is time-efficient and can recover useful structural information even when the inhomogeneous line broadening leads to overlap of neighboring resonances in the conventional COSY spectrum. Theoretical expression of the resulting signals was deduced based on intermolecular multiple-quantum coherence treatment in combination with distant dipolar field treatment. Experiments were performed to verify its feasibility and advantages over previous methods.