A sensitive and practical procedure has been developed for the determination of the sn-1-alk-1-enyl-2-acylglycerol moieties of natural glycerophospholipids using capillary gas-liquid chromatography with flame ionization detection. The method gives excellent resolution and quantitative estimates for molecular species according to carbon number and degree of unsaturation. The diradylglycerols are released from the glycerophospholipids by hydrolysis with phospholipase C and the alk-1-enylacylglycerols are resolved by thin-layer chromatography. Either the trimethylsilyl or the tertiary-butyldimethylsilyl ethers are then resolved at 250 degrees C by gas-liquid chromatography on a glass capillary column wall-coated with a polar cyanopropylsiloxane polymer using hydrogen as the carrier gas. The method has been applied to the analysis of the alk-1-enylacyl- and diacyl-glycerol moieties of the phosphatidylethanolamines of rat heart and kidney.