Novel PVC-based coated graphite electrode for selective determination of quinoline yellow

Novel coated graphite electrode (CGE) for the determination of quinoline yellow (QY), an artificial food colorant, was evaluated based on the use of tetraphenylphosponium-QY ion-pair complex as the electroactive substance. The electrode revealed linear emf-pQY response over wide concentration ranges (1.0 × 10−1 ∼ 5.0 × 10−5 M) with a slope −30.1 ± 0.2 mV decade−1 and a limit of detection of 4.0 × 10−5 M. The electrode showed good stability, reproducibility and fast response (<5 s). It can be used in wide pH range (4.7–10.7) and was successfully applied to determination of quinoline yellow in artificial mixtures and commercial soft drinks. The results obtained with the electrode were in good agreement with the value obtained by using HPLC measurements, as an official method.