A rapid gas-liquid chromatographic method for the multi-determination of antioxidants in fats, oils and dried food products.

A rapid quantitative method for determining 8 antioxidants in various food products is described. Two procedures are employed. The first involves the use of a glass wood precolumn to separate 3(2)-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxytoluene, 4-hydroxymethyl-2,6-di-tert-butylphenol, and mono-tert-butylhydroquinone (TBHQ) from nonvolatile residues resulting from direct injection of diluted sample or sample extracts into the gas-liquid chromatographic (GLC) column. In the second procedure, the antioxidants TBHQ, 3,3'-thiodipropionic acid, n-propyl gallate, 2,4,5-trihydroxybutyrophenone, and nordihydroguaiaretic acid are isolated from food products by extraction with 70% ethanol. The antioxidant residues are then converted to trimethylsilyl derivatives, and determined by GLC, using a flame ionization detector. Recoveries of all 8 antioxidants from 28 food samples fortified at either 10 or 100 ppm ranged from 70 to 105%.