This GSO Standard specifies a thin-layer chrotomagraphic method for the detection and identification of the following antioxidants in animal and vegetable fats and oils: – propylgallate (PG) – octylgallate (OG) – dodecylgallate(DG) – tertiary butyl hudro quinone (E 319) – butylhydroxyanisole (tert- butyl- 4- methoxyphenol) (BHA) – tocopherol – butylhydroxytoluene (2,6- di- tert- butyl - 4- methylphenol) (BHT) The antioxidants are listed in the order of their Rf values. The detection of ?-tocopherol is sometimes difficult as the spots of this antioxidant are of a generally diffuse aspect. The method has limits of detection of 20 (ppm) for BHT, and 10 (ppm) for the other antioxidants. It should be noted that BHT is not completely isolated by this method.