Quantitative determination of the phenolic antioxidants using voltammetric techniques

Synthetic antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), show sensitivity to voltammetric waves. The waves of these antioxidants, however, are seriously overlapped and it is difficult to determine them simultaneously. The influence of different parameters (working electrode, supporting electrolyte, pH, voltammetric technique) was evaluated in a quantitative simultaneous determination of three antioxidants in alcoholic mixtures and real sample foods. Glassy carbon (GC) and platinum (Pt) working electrodes were investigated as mediators of oxireduction reactions. Two supporting electrolytes were investigated: Britton–Robinson 0.1 mol l−1 buffer (pH 2.0) and HCl 0.1 mol l−1 (pH 2.0) both with 2 g l−1 (p/v) of methanol. In this paper, voltammetric conditions for the analysis of up to three-component mixtures of antioxidant present at levels: 2.0–100.0 mg l−1 for BHA, 4.0–100.0 mg l−1 for TBHQ and 2.0–20.0 mg l−1 for BHT at GC in HCl 0.1 mol l−1 and 8.0–120.0, 10.0–130.0 and 4.0–30.0 mg l−1 for BHA, TBHQ and BHT, respectively, at Pt in the same supporting electrolyte. The results show that for real food samples, the parameters investigated were satisfactory for quantitative determination using square wave voltammetry (SWV) without chemometric approaches and without suffering overlapping problems.