Voltammetric determination of tert-butylhydroxyanisole in micellar and emulsified media

A voltammetric study of the oxidation process of the antioxidant tert-butylhydroxyanisole (BHA) in miceller and emulsified media is described. The non-ionic surfactant Pluronic F-68, in Britton-Robinson buffer at pH 2.0, was found to be the most suitable surfactant for the determination of BHA in micellar solutions. The characteristics of the oxidation process were established. An emulsified medium formed with ethyl acetate as organic solvent and Pluronic F-68 as emulsifying agent was also used. Linear calibration graphs for BHA were obtained by differential pulse voltammetry with the ranges 1.0×10−6−1.0×10−5 mol l−1 and 1.0×10−5−5.0×10−5 mol l−1. The limits of determination were found to be 1.3×10−6 mol l−1 and 8.5×10.−7 mol l−1 BHA in micellar and emulsified media, respectively. Interferences from BHT (tert-butylhydroxytoluene), TBHQ (tert-butylhydroquinone), citric acid, propyl gallate and propylene glycol were tested. The method was applied to the determination of BHA in chewing gum samples by direct emulsification of an aliquot of the antioxidant extract from the sample in ethyl acetate.