Reference deconvolution: A simple and effective method for resolution enhancement in nuclear magnetic-resonance spectroscopy

Linewidths and line shapes are key criteria determining the utility of a nu clear magnetic resonance (NMR) spectrum, and considerable effort is usually devoted to shimming the magnetic held (B-0) to ensure optimum resolution. However, even if the external Field is almost perfectly homogeneous, the sa mple itself can induce gradients owing to susceptibility effects from its o verall shape or internal heterogeneity. Thus, magnetic field gradients near ly always contribute significantly to the linewidths and shapes in an NMR s pectrum. Reference deconvolution is a technique which uses the shape of a s ingle resonance line to measure the actual frequency distribution produced by the local B-0 inhomogeneity and then deconvolves that distribution from the whole spectrum. It is a simple linear process which requires no prior k nowledge of the number of lines, their intensities, or their relaxation cha racteristics. No fitting procedures are used. This article reviews the refe rence deconvolution method, demonstrates its application to one-dimensional NMR spectroscopy, and discusses the tradeoffs between resolution and signa l/noise. (C) 2000 John Wiley & Sons, Inc.