J-coupling in NMR-spectra of Organophosphorus Liquids in Earth's Magnetic Field

NMR measurements in low and ultra-low magnetic fields can become a way to distinguish organic liquids. The spectral splitting in the NMR spectra taken at very low fields is due to indirect spin-spin interaction (J-coupling), while no chemical shift information is usually available. Therefore, J-splittings are the only effect that distinguishes spectra in a low field. In this work, Earth's magnetic field NMR-spectra from three various organophosphorus substances have been measured using low-cost equipment. We have shown that the EF-NMR spectra of various liquids with similar structures are significantly different from each other. The analysis of spectra has been carried out and the results are compared with the literature data.