POLAROGRAPHIC-DETERMINATION OF TERT-BUTYLHYDROQUINONE IN MICELLAR AND EMULSIFIED MEDIA

A polarographic study of the oxidation of tert-butylhydroquinone (TBHQ) in micellar and emulsified media is described. The non-ionic surfactant Pluronic F-68, in Britton-Robinson buffer (pH 9.0), was found to be the most suitable for determining this antioxidant in micellar solutions. The characteristics of the oxidation process were established. Linear calibration graphs were obtained for TBHQ by differential-pulse polarography (DPP) within the ranges 1.0 X 10(-6)-1.0 X 10(-5) and 1.0 x 10(-5)-1.0 x 10(-4) Mol l-1 with a limit of determination (10 x standard deviation) of 6.7 x 10(-7) Mol l-1 TBHQ (0.11 mg l-1). An emulsified medium formed with a mixture of hexane and ethyl acetate (99: 1) at pH 8.0 was also used. Linear calibration graphs were obtained by DPP within the ranges 1.0 X 10(-6)-1.0 X 10(-5) Mol l-1 and 1.0 X 10(-5)-1.0 X 10(-4) mol l-1 TBHQ. The limit of determination was found to be 8.3 x 10(-7) Mol l-1. Interferences from tert-butylhydroxyanisole, tert-butylhydroxytoluene, citric acid, propyl gallate and propylene glycol were tested. Except for propyl gallate, none of them interfered. The proposed method was applied with good results to the determination of TBHQ in spiked edible oils by direct emulsification of the samples.