Resolving chemical shift spectra with a low-field NMR relaxometer

The possibility of obtaining high-resolution NMR spectra with a relaxometer at comparatively low and weakly inhomogeneous constant magnetic field is demonstrated experimentally. By modifying the radio frequency coil to produce a linear B1 field, apparent free induction decay signals can be observed by stroboscopic acquisition of nutation echoes. Spectra of toluene and ethanol are reported. As it turns out, better chemical shift resolution can be obtained by placing the sample into a region of well defined field inhomogeneity than placing it into the most homogeneous part of the field.