Ultrasensitive and simultaneous determination of the isomers of Amaranth and Ponceau 4R in foods based on new carbon nanotube/polypyrrole composites

In the present work, a novel strategy based on new carbon nanotube (CNT) and polypyrrole (ppy) composite modified electrode for the simultaneous determination of the isomers of Amaranth (E123) and Ponceau 4R (E124) was proposed. Due to the increasing dispersibility and effective surface area of the CNT caused by decoration of ppy to the CNT, the proposed electrode exhibited excellent electrochemical sensitivity and high selectivity toward the oxidation of Amaranth and Ponceau 4R. The linear response ranges for Amaranth and Ponceau 4R were 5.0 × 10−9 M–5.0 × 10−7 M, and 8 × 10−9 M–1 × 10−6 M and corresponding detection limits as low as 5.0 × 10−10 M and 1.0 × 10−9 M, respectively. roposed method was successfully applied in the detection of Ponceau 4R and Amaranth in fruit drink samples.