High-performance liquid chromatographic determination of several 2-alkenals, specially acrolein, crotonaldehyde, 2-pentenal, 2-hexenal, 2-heptenal, 2-octenal and 2-nonenal, were studied using the precolumn derivatization reagent 2, 4-diaminotoluene. After the selective condensation of these 2-alkenals to form fluorescent 7-amino-6-methylquinoline derivatives, separation of these compounds was achieved on a ODS column (150×4 mm i.d.) with a linear gradient system of acetonitrile and 50 mM mono-ammonium phosphate containing 5 mM sodium 1-octanesulfonate (from 20% acetonitrile to 60% acetonitrile in 1 h), and the separated quinoline derivatives were detected with a fluorescence monitor (396 nm for excitation and 485 nm for emission). There autooxidized unsaturated fatty acid methyl esters and five autooxidized edible oils were subsequently assayed for acrolein (C₃), crotonaldehyde (C₄), 2-pentenal (C₅), 2-heptenal (C₇), 2-octenal (C₈) and 2-nonenal (C₉). The peak of 2-hexenal was interfered with the unknown peak derived from oxidized lipids. Their detection limits (S/N=2) were 10, 10, 25, 25, 50, 50 pg for acrolein, crotonaldehyde, 2-pentenal, 2-heptenal, 2-octenal and 2-nonenal, respectively.