P-31 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 P-31 NMR spect roscopy in a mixture of triethylamine, dimethylformamide and guanidinium ch loride. Higher dispersion of the P-31 NMR signals and better reproducibilit y 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 identificati on of all the components in the P-31 NMR spectra of complex phospholipid mi xtures, which was not feasible using the chloroform-methanol-water system. The efficiency of the new solvent was tested on crude lipid extracts from d ifferent biological sources such as lecithin, mouse mammary carcinoma, porc ine stomach, porcine spleen, porcine brain, human red blood cells, yeast, f ungi and tuna fish muscle. The reproducibility of the chemical shift of the phospholipid signals was demonstrated in the presence of various amounts o f neutral lipids (triglycerides) and sterols, which are commonly present in the Folch extracts. (C) 1998 John Wiley & Sons, Ltd.