Analysis of Mixtures of Phospholipids in Dimethylformamide

It was recently shown that the 31P-NMR analysis of phospholipids gains in resolution, stability and reproducibility if a mixture of dimethylformamide, triethylamine and guanidinium chloride is used as solvent (1). In such solvent, both a higher dispersion and a narrower line broadening of the 31 P signals can be obtained also for complex mixtures of phospholipids. In order to recognize the phospholipid species, a series of 1D pulsed-field-gradient decoupled 1 H- 31PHMBC NMR experiment were performed selecting the 31 P resonances of all the components of the mixtures. The gradient-enhanced version of the pulse sequence was preferred for the outstanding solvent suppression achieved. This method allows the assignment of most of the 1 H resonances of the different phospholipids in the proton NMR spectrum.