SIMULTANEOUS KINETIC DETERMINATION OF BUTYLATED HYDROXYANISOLE AND PROPYL GALLATE BY COUPLING STOPPED-FLOW MIXING TECHNIQUE AND DIODE-ARRAYDETECTION

Kinetic methodology was used for the first time to develop a simple, f ast photometric method for the simultaneous determination of two food antioxidants, namely butylated hydroxyanisole (BHA) and propyl gallate (PG). The method is based on the different kinetic behaviour of these compounds when react with 3-methylbenzothiazolin-2-one hydrazone in t he presence of cerium(IV) and on the joint use of the stopped-flow mix ing technique and a diode-array detector, which allowed to obtain kine tic data at two wavelengths simultaneously. Calibration graphs were li near over the range 0.3-30 mu g ml(-1) for BHA and 1.6-27.5 mu g ml(-1 ) for PG. The relative standard deviation was 1.0-2.1%. Both antioxida nts were determined simultaneously by using a system of two equations which Nas resolved by multiple linear regression. Mixtures of BHA and PG in ratios between 4 : 1 and 1 : 10 were satisfactorily resolved, Th e method was applied to the determination of these antioxidants in sev eral food samples. Analytical recoveries ranged between 97.2 and 103.5 %, (C) 1997 Elsevier Science B.V.