Direct detection of BHA in food samples using oil/water interface electrochemistry as main tool.

Analysis of BHA (tert-butyl-4-hydroxyanisole), a very common food additive, is commonly carried out by chromatographic techniques [1-3]. On the other hand, the intention of this research is to promote a simple and effective detection of BHA using electrochemistry, since that can present lower cost and could be more effective than the conventional methodologies of analysis. We describe here the direct detection of BHA using oil/water electrochemistry in conjunction with the square wave voltammetry (SWV) technique as main tools to promote this type of analysis. BHA determination was performed with a catodically pre-treated Boron-Doped Diamond (BDD) plate as working electrode, which was inserted directly at the interface, constituted by an oily solution of BHA and a conventional aqueous phase (Britton-Robinson buffer). Figure 1 shows a schematic representation of the electrochemical cell. The position of the BDD electrode at the interface must be carefully controlled, avoiding area differences. Preliminary tests indicated that BHA oxidation is an irreversible process and the generated oxidation product is also electroactive. The partitioning of BHA reaches an equilibrium situation at around 15 minutes of contact between oil and aqueous phase. All experiments were carried out by SWV. Figure 2 shows the electrochemical responses after completing the partitioning of BHA from oil to aqueous phase. BHA concentrations were vary from 9,7 x 10-2 to 1,2 x 10-1 mol L-1. In this experiment, a very good linearity was observed, with an R² of 0,98. It was possible to conclude that the methodology is feasible and the use of a catodically pre-treated BDD electrode can constitute a good choice to promote this type of study.