Gas-liquid chromatographic determination of tertiary-butylhydroquinone (TBHQ) in dried fish, frozen shrimp, vegetable oils, butter, and margarine.

Tertiary-butylhydroquinone (TBHQ) is extracted from foods with ethyl acetate, the solvent is evaporated, the residue is dissolved in n-hexane-ethyl acetate (99 + 1), and the TBHQ is selectively transferred into an aqueous layer (2% sodium chloride) as a separation from food interferences. Finally, TBHQ is reextracted with n-hexane-ethyl acetate (1 + 1), concentrated, and determined by flame ionization gas-liquid chrmoatography. Dried fish, frozen shrimp, vegetable oils, and edible fats were analyzed by the method. More than 85% was recovered when the samples were fortified with 100 ppm TBHQ. Detection limit was 1.0 ppm TBHQ.