Square‐Wave Voltammetry Determination of Aspartame in Dietary Products Using a Boron‐Doped Diamond Electrode

Abstract

The use of square‐wave voltammetry in conjunction with a cathodically pretreated boron‐doped diamond electrode for the analytical determination of aspartame in dietary products is described. In this determination, the samples were analyzed without previous treatment in a 0.5 mol l⁻¹ H₂SO₄ solution. A single oxidation peak at a potential of 1.6 V vs. Ag/AgCl (3.0 mol l⁻¹ KCl) with the characteristics of an irreversible reaction was obtained. The analytical curve was linear in the aspartame concentration range 9.9×10⁻⁶ to 5.2×10⁻⁵ mol l⁻¹ with a detection limit of 2.3×10⁻⁷ mol l⁻¹. The relative standard deviation (n=5) obtained was smaller than 0.2% for the 1.0×10⁻⁴ mol l⁻¹ aspartame solution. The proposed method was applied with success to the determination of aspartame in several dietary products and the results were similar to those obtained using an HPLC method at 95% confidence level.

Keywords:

• Aspartame
• boron‐doped diamond electrode
• cathodic pretreatment
• square‐wave voltammetry

The authors acknowledge fellowships and the financial support from Brazilian agencies: FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico).