31P nuclear magnetic resonance analysis of phospholipids in a ternary homogeneous system.

We analyzed the changes in the shape and resonance positions of the 31P NMR signals of phospholipid mixtures in a single-phase solvent containing different quantities of chloroform, methanol, and water. We obtained extremely reproducible NMR signals when sufficient care was taken to control the desired solvent composition. The solvent composition can be predicted using a "tie line" in a ternary diagram of chloroform, methanol, and water or by mixing the three components at the desired ratio. Avoiding the presence of a biphasic system allows easy solvent preparation and NMR spectral reproducibility, with the possibility of complete recovery of the sample and absence of loses due to different repartition coefficients.