Determination of optimization parameters based on the Box-Behnken design for cloud point extraction of quinoline yellow using Brij 58 and application of this method to real samples.

Quinoline yellow (E104) dye is a food additive and generally used in cosmetics and drugs. In this work, polyethylene glycol hexa decyl ether (Brij 58) was used for the spectrophotometric determination of quinoline yellow (QY) in food and drug samples after cloud point extraction (CPE). Some parameters such as extraction temperature and time, pH, centrifuge speed, Brij 58 (surfactant) concentration, and Na2SO4 concentration were optimized using Box-Behnken design. The limit of detection (LOD) of this method was 0.0019 µg mL-1 for QY while the relative standard deviation (RSD) at low concentration levels (0.03 µg mL-1) was 1.32% (n = 5). Findings indicated that, this novel CPE method can be used quickly for the reproducible, selective and sensitive determination of QY dye in ordinary analysis.