Simultaneous square-wave voltammetric determination of aspartame and cyclamate using a boron-doped diamond electrode

A simple and highly selective electrochemical method was developed for the simultaneous determination of aspartame and cyclamate in dietary products at a boron-doped diamond (BDD) electrode. In square-wave voltammetric (SWV) measurements, the BDD electrode was able to separate the oxidation peak potentials of aspartame and cyclamate present in binary mixtures by about 400 mV. The detection limit for aspartame in the presence of 3.0 × 10−4 mol L−1 cyclamate was 4.7 × 10−7 mol L−1, and the detection limit for cyclamate in the presence of 1.0 × 10−4 mol L−1 aspartame was 4.2 × 10−6 mol L−1. When simultaneously changing the concentration of both aspartame and cyclamate in a 0.5 mol L−1 sulfuric acid solution, the corresponding detection limits were 3.5 × 10−7 and 4.5 × 10−6 mol L−1, respectively. The relative standard deviation (R.S.D.) obtained was 1.3% for the 1.0 × 10−4 mol L−1 aspartame solution (n = 5) and 1.1% for the 3.0 × 10−3 mol L−1 cyclamate solution. The proposed method was successfully applied in the determination of aspartame in several dietary products with results similar to those obtained using an HPLC method at 95% confidence level.