Simultaneous determination of Tropaeolin O and brilliant blue in food samples after cloud point extraction

In this study, a simple and low-cost method was developed for extraction and pre-concentration of brilliant blue(BB) and Tropaeolin O(TO) in food samples using cloud point extraction (CPE) prior to spectrophotometric determination. The effects of main factors such as pH, surfactant and salt concentrations, incubation time and temperature on the cloud point extraction of both dyes were investigated and optimized. Linear range of calibration curves were obtained in the range of 50–4000 ng mL^−1 for BB and 50–5000 ng mL^−1 for TO under the optimum conditions. The limit of detection values for BB and TO was 10 and 20ng mL^−1, respectively. The relative standard deviation (RSD) values of both dyes for repeated measurements (n=6) were less than 2.2 %. The obtained results demonstrate that the proposed method can be applied satisfactorily to determine these dyes in different food samples.