High performance liquid chromatography (HPLC) with a cyanopropyl phase column coupled directly to a commercial HPLC flame ionization detector (FID) and a gradient mobile phase of tert-butyl ether and hexane proved successful to separate and quantitate mono-, di-, and triacylglycerols, free fatty acids and methyl esters. These components can occur together during glycerolysis, lipolysis, randomization, and interesterification reactions of vegetable oils like soybean. Gravimetric standards were evaluated by HPLC-FID in which each contained mono-, di, and triacylglyceols, free fatty acids and methyl esters of palmitic. stearic, oleic, linoleic, and linolenic acids respectively. The FID response with solute weight decreased in this order: triacylglycerols, free fatty acids, diacylglycerols, methyl esters, and monoacylglycerols, respectively. The FID thus required response factors to quantitate the components of mixtures of diverse lipid species. However, for homogenous compounds the FID response was linear and response factors were not required, for example, for a series of free fatty acids like palmitic through linolenic. The commercial HPLC-FID proved satisfactory for facile quantitation of diverse lipid species in vegetable oil reaction mixtures. Good accuracy was obtained by HPLC with FID for soybean glycerolysis products, which contained mono, di and triacylglycerols.