Improved resolution using symmetrically shifted pulses

An approach to Hadamard phase encode the two halves of the F-1 dimension of a gHSQC experiment is presented. The phase encoding is achieved by excitation sculpting of the F-1 dimension using symmetrically shifted pulses. This approach (IMPRESS-improved resolution using symmetrically shifted pulses) increases the resolution of the F-1 dimension by exploiting spectral folding, but the folding is coded in the fashion of a Hadamard H-2 matrix. Editing of the IMPRESS spectra during processing sorts out spectral crowding which is a typical consequence of F-1 spectral folding. It is shown that for the same total experiment time, the IMPRESS-gHSQC experiment provides narrower peaks along the F-1 dimension compared to the normal gHSQC experiment. As a consequence of decreased linewidth, the peak height (sensitivity) is also increased. (C) 2001 Academic Press.