Broadband proton-decoupled proton spectra.

We present a new method for recording broadband proton-decoupled proton spectra with absorption mode lineshapes and substantially correct integrals; in both these respects, the new method has significant advantages over conventional J-spectroscopy. In our approach, the decoupled spectrum is simply obtained from the 45 degrees projection of the diagonal-peak multiplets of an anti z-COSY spectrum. This method is straightforward to apply, and does not require any unusual data processing. However, there is a significant reduction in sensitivity when compared to a conventional proton spectrum. The method is demonstrated for typical medium-sized molecules, and it is also shown how such a decoupled spectrum can be used to advantage in measurements of diffusion constants (DOSY), the measurement of relaxation parameters, and the analysis of complex mixtures.