Voltammetric Determination of Indigo Carmine and Amaranth on a Silver-Based Mercury Film Electrode

Abstract
The voltammetric behavior of indigo carmine and amaranth on silver-based mercury film electrodes was studied. At pH 4, reduction current peaks were observed at potential −0.11 V (indigo carmine) and −0.24 V (amaranth), respectively. The system showed a linear response to both of the food colorants in a concentration range of 0 to 100 ng/ml. Detected at different reduction potentials, indigo carmine and amaranth could be determined separately without interfering with each other. This method demonstrated a better reproducibility and longer life time than the existing techniques.