Effect of magnetic particles on NMR spectra of Murchison meteorite organic matter and a polymer-based model system

Organic matter from the Murchison meteorite shows pronounced spinning sidebands of the 1H MAS NMR spectrum and exhibits a large bulk magnetization of 0.75 emu/g extrapolated to 94 kOe at 300 K. By comparison with data of diamagnetic polystyrene and laponite clay mixed with ferrimagnetic γ-Fe2O3 nano-particles, we show that the spinning sidebands arise from a combination of dipolar couplings of a given 1H to magnetic particles, seen in a backscattered-electron image, and to other protons. Signal loss and significant broadening of protonated-carbon peaks in 13C MAS NMR spectra of polystyrene with Fe2O3 nano-particles is demonstrated, and implications for 13C NMR spectroscopy of Murchison meteorite are discussed.