31P NMR ANALYSIS OF PHOSPHOLIPIDS IN CRUDE EXTRACTS FROM DIFFERENT SOURCES: IMPROVED EFFICIENCY OF THE SOLVENT SYSTEM

Crude lipid extracts from different tissues were analysed by 31P NMR spectroscopy in a mixture of triethylamine, dimethylformamide and guanidinium chloride. Higher dispersion of the 31P NMR signals and better reproducibility of the chemical shifts were achieved with respect to the spectra acquired in the conventional chloroform–methanol–water solvent. In particular, the reproducibility of the chemical shifts allowed the unambiguous identification of all the components in the 31P NMR spectra of complex phospholipid mixtures, which was not feasible using the chloroform–methanol–water system. The efficiency of the new solvent was tested on crude lipid extracts from different biological sources such as lecithin, mouse mammary carcinoma, porcine stomach, porcine spleen, porcine brain, human red blood cells, yeast, fungi and tuna fish muscle. The reproducibility of the chemical shift of the phospholipid signals was demonstrated in the presence of various amounts of neutral lipids (triglycerides) and sterols, which are commonly present in the Folch extracts. © 1998 John Wiley & Sons, Ltd.