Improvement of the sensitivity of the two-dimensional asynchronous spectroscopy based on the AOSD approach by using a modified reference spectrum

In this paper, a modified reference spectrum is utilized to generate 2D asynchronous spectra constructed by using the AOSD approach that is developed in our previous work. Mathematical analysis suggests that it is possible to enhance the intensity of cross peaks by using the modified reference spectrum. Computer simulation indicates that both intensity of cross peaks and signal-to-noise ratio of 2D spectra are improved significantly by adopting the modified reference spectrum. As a result, 2D asynchronous spectrum can be used to probe weak intermolecular interactions under the influence of spectral noise. Furthermore, experiments on acetonitrile/butanone/CCl4 system demonstrate that intensities and signal-to-noise ratio of cross peaks that reflect intermolecular interactions between acetonitrile and butanone can be enhanced remarkably by using the modified reference spectrum.

► A modified reference spectrum is used to construct 2D asynchronous spectra.
► Computer simulation show intensities and s/n ratio of cross peaks are improved.
► Experiments on real chemical system show intensities of cross peaks are enhanced.