Liquid-chromatographic estimation of saturated phospholipid palmitate in amniotic fluid compared with a thin-layer chromatographic method for acetone-precipitated lecithin.
The "high-performance" liquid-chromatographic method we report for measuring palmitate derived from saturated phospholipids in amniotic fluid is sensitive and precise and possesses a wide dynamic range. Palmitate from nonsurfactant sources is largely excluded. The procedure involves oxidation of the chloroform/methanol-extracted lipids with osmium tetroxide, precipitation of the resulting phosphatides with cold acetone, mild alkaline hydrolysis, derivatization of the liberated fatty acids to phenacyl esters, and reversed-phase chromatography. The method is no less convenient or more time-consuming than measurement of the lecithin/sphingomyelin ratio by thin-layer chromatography. The clinical usefulness of the procedure is indicated by results of a correlative study of 26 amniotic fluids evaluated by "lung profile" tests in a second laboratory. A value for dipalmitoyl lecithin of 13 mg/L or greater indicates fetal lung maturity.
D000096:Acetone; D000653:Amniotic Fluid / Q000032:analysis*; D011232:Chemical Precipitation; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005260:Female; D005325:Fetal Organ Maturity; D006801:Humans; D007202:Indicators and Reagents; D008168:Lung / Q000196:embryology; D010168:Palmitates / Q000032:analysis*; D010169:Palmitic Acids / Q000032:analysis*; D010713:Phosphatidylcholines / Q000032:analysis*; D010743:Phospholipids / Q000032:analysis*; D011247:Pregnancy; D013109:Sphingomyelins / Q000032:analysis
D007202:Indicators and Reagents; D010168:Palmitates; D010169:Palmitic Acids; D010713:Phosphatidylcholines; D010743:Phospholipids; D013109:Sphingomyelins; D000096:Acetone