Synthetic antioxidants in edible oils by square-wave voltammetry on ultramicroelectrodes

Square wave voltammetry (SWV) on carbon disk ultramicroelectrodes (UME) was used to determine antioxidants terf-butylhydroxyanisole (BHA) and tert-butylhydroxytoluene (BHT) in vegetable oils. Direct determinations were accomplished in benzene/ethanol/H2SO4 solutions or in acetonitrile (ACN) after an extractive procedure. Much better recovery percentages were obtained in ACN extracts. By comparing with high-performance liquid chromatography (HPLC) results, BHA has a slightly lower recovery percentage by the SWV technique on ACN extracts. On the other hand, BHT shows a greater recovery percentage using the methodology proposed here. The analysis time through SWV is less than an hour for a duplicated analysis while the HPLC technique needs a greater time, besides the overnight stored time required by the current methodology. The present work tends to show that SWV on carbon disk UME allows sensitive, reproducible, and faster determination of BHA, BHT, or antioxidant mixtures in oil-solvent solutions or after a simple extractive procedure with the advantage of a higher recovery percentage. This validates the methodology as an analytical alternative for antioxidant quantification.