In order to carry out simultaneous determination of six kinds of synthetic antioxidant in edible oils, the oil was dissolved in pentane and extracted with acetonitrile saturated with pentane. A definite quantity of benzophenone was added to the extract as internal standard, and the solution was concentrated by Kuderna-Danish concentrator. A small amount of the oil that separated from antioxidants on thin-layer chromatogram was removed, and extracted antioxydants and benzophenone were submitted to gas-liquid chromatography as a trimethylsilane derivatives. Recovery rates of n-propyl gallate and iso-amyl gallate were slightly lower and precisions of determination were also lower than others, however, the determimatien of butyl hydroxy anisol, dibutyl hydroxy toluene, ethyl protocatecuate and nordihydroguaiaretic acid were fully satisfactory.
