To a question on possibilities of high-resolution NMR spectroscopy in the Earth magnetic field

Abstract

The low signal-to-noise ratio is a characteristic feature of NMR experiments in the Earth magnetic field. The main problem of such studies is the ineffectiveness of signal accumulation due to fluctuations of the Earth magnetic field because of magnetic interferences from laboratory equipment and other magnetic field sources. Taking into account the fact that generally in the Earth magnetic field proton-containing liquids have spectra with a central strong line, a relatively simple method has been found to neutralize the Larmor frequency fluctuations. The NMR signal processing algorithm is described. The home-built NMR-equipment allows us to clearly register the splitting in proton spectra, for example, due to the J-interaction with such nuclei as 29Si or 13C at their natural abundance (4.7 and 1.1%, respectively).