Two-dimensional NMR spectroscopy in Earth's magnetic field

J Magn Reson. 2006 Oct;182(2):343-7. doi: 10.1016/j.jmr.2006.06.027. Epub 2006 Jul 24.


We demonstrate the first two-dimensional correlation NMR (COSY) spectra obtained at ultra low frequencies (ULF) using the Earth's magnetic field. Using a specially developed spectrometer with multiple audio-frequency pulses under controlled pulse phase, we observe magnetisation transfer arising from heteronuclear J-couplings in trifluoroethanol and para-difluorobenzene. The 2D COSY spectra exhibit all diagonal and off-diagonal multiplets consistent with known J-couplings in these molecules.