Determination of tert-Butylhydroquinone in Oily Foods and Dried Fish

Abstract

A method for quantitative determination of tert-butylhydroquinone (TBHQ) in oily foods and dried fish by high performance liquid chromatography was developed. TBHQ was extracted from foods with ethyl acetate, the solvent was evaporated off, and the residue was dissolved in n-hexane-ethyl acetate mixture (99:1, v/v%). The n-hexane-ethyl acetate mixture was applied to an Extrelut column for extraction and clean-up of TBHQ. The Extrelut column gave an eluate free from emulsion with a high yield of TBHQ. TBHQ was separated on a reverse-phase column, “LiChrosorb RP-8” (4.0mm×15cm), by using acetonitrile/0.01M monobasic potassium phosphate solution (50/50v/v%). Detection was done by absorption measurement at 282nm with 0.04 AUFS. Isoamyl p-hydroxybenzoate was used as an internal standard. Normal phase chromatography with a “LiChrosorb DIOL” column (4.0mm×50cm) was employed for confirmation of TBHQ with 25% ethyl acetate in n-heptane as the mobile phase.Recoveries of TBHQ from foods were in the range of 91.2-95.1%. The present method permits a simple determination of TBHQ at a level as low as 1.0ppm in oily foods and dried fish.