High-resolution nmr spectroscopy with a portable single-sided sensor, Science 308

Unlike absorption and fluorescence spectrome-ters, nuclear magnetic resonance (NMR) instru-ments are not easily miniaturized for field use. Portable NMR systems have been built, with open single-sided probes for arbitrarily sized samples (1). However, the unavoidable spatial in-homogeneity of the static magnetic field has precluded the use of these devices for high-resolution spectroscopy. These field variations are usually orders of magni-tude larger than those created by the microscopic structure of the molecules to be detected, so no chemical shift infor-mation can be extracted from the spectra. Thus far, the systems have mainl