NMR study of the potential composition of Titan׳s lakes

• 1H and 13C chemical shifts in of the major constituents in Titan׳s lakes are obtained.
• The 1H and 13C NMR spectra of lake composition are simulated on a 1 T NMR.
• The lake composition can be determined from either quantitative 1H or 13C spectra.
• The proton T1 relaxation times are determined for quantitative NMR.
• The gas solubility of these organics is investigated in hydrocarbon solutions.

A large number of hydrocarbon lakes have been discovered in Titan׳s surface. However, the chemical composition and physical properties of these lakes are not fully understood. We investigate the potential composition of Titan׳s lakes by NMR. Based upon NMR data, the 1H and 13C NMR spectra of the hydrocarbons in Titan׳s lakes are simulated on a 1 T spectrometer [being developed at the NASA Jet Propulsion Laboratory (JPL) for future in situ characterization of Titan׳s lakes]. The study indicates that the dominant composition (all components>1% of the lake composition by mole fraction) in Titan׳s lakes can be determined and the major soluble organics quantitatively identified from either quantitative 1H or 13C spectra on a 1 T NMR spectrometer. The proton T1 relaxation times are determined for a number of candidate organics in hydrocarbon solution, a necessary determinant for quantitative NMR. The gas solubility of these organics is also investigated to understand the equilibrium of composition between Titan׳s lakes and atmosphere and the precipitation rates of the molecules at Titan׳s ground level. Our results are significant for the ongoing discussion regarding the development of in situ, low bias analysis methods and instruments for Titan missions and other outer planet exploration.