Organic solvent systems for 31P nuclear magnetic resonance analysis of lecithin phospholipids: applications to two-dimensional gradient-enhanced 1H-detected heteronuclear multiple quantum coherence experiments.
31P NMR of lipid extracts is a reproducible, rapid, and nondegradative method for qualitative and quantitative analyses of phospholipid mixtures. This analysis, however, is hampered by the instability of the solvent system commonly used for NMR spectroscopy (CHCl3/ CH3OH/H2O-EDTA). In this work we have investigated the effects of several monophasic solvent mixtures to overcome this disadvantage. Among these mixtures we have selected a solution of triethylamine, dimethylformamide, and guanidinium chloride (Et3N/DMF-GH+) as the most efficient system. In this solvent the chemical shift dispersion of the 31P signals is about four times the frequency range observed in the standard chloroform-methanol-water system. Moreover, the stability of this solvent, as a monophasic system, allows easy reproducibility of the analysis. The use of two-dimensional 1H-31P gradient-enhanced heteronuclear multiple quantum coherence experiments can further exploit the higher resolution of the signals obtained with this solvent system for the structure elucidation of known and unidentified phospholipids.
Bosco
M
M
POLY-biós Research Centre, Area Science Park, Trieste, Italy.
Culeddu
N
N
Toffanin
R
R
Pollesello
P
P
D000081:Acetamides; D000085:Acetates; D001554:Benzene; D002725:Chloroform; D004126:Dimethylformamide; D004146:Dioxanes; D005021:Ethylamines; D005663:Furans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010713:Phosphatidylcholines / Q000737:chemistry*; D011725:Pyridines; D011789:Quantum Theory; D012997:Solvents; D013696:Temperature; D014867:Water
D000081:Acetamides; D000085:Acetates; D004146:Dioxanes; D005021:Ethylamines; D005663:Furans; D010713:Phosphatidylcholines; D011725:Pyridines; D012997:Solvents; D014867:Water; C018674:tetrahydrofuran; C007650:ethyl acetate; D002725:Chloroform; D004126:Dimethylformamide; D001554:Benzene; C025223:1,4-dioxane; C013959:dimethylacetamide; C023666:pyridine; C016162:triethylamine