In most 2D NMR spectra the position of the peaks, the chemical shift, is the most important piece of information. If splitting of the peaks by scalar coupling is observed, it is usually ignored. In fact, in many cases scalar coupling in 2D experiments can be detrimental. The splitting increases the chance of overlap and makes it harder to determine accurately the chemical shift. Pure shift experiments, in which the scalar coupling is removed, do not have these problems and are also more sensitive because the peaks are narrower and taller. Heteronuclear 2D experiments, such as HSQC, can be converted to pure shift experiments without loss of sensitivity by applying broad band homo decoupling during acquisition.
