Determination of Violet Covasol as a cosmetic dye in water samples by a CPE-Scanometry method

The trace amounts of Violet Covasol as a cosmetic dye was determined by an efficient cloud point extraction-Scanometry (CPE-Scanometry) method. This method has many advantages such as novelty, facility, high speed, sensitivity, low cost and safety. The method is based on the CPE of an analyte from an aqueous solution, diluting the extracted surfactant-rich phase with ethanol, transferring to Plexiglas^® cell and scanning of the cells containing the analyte solution with a scanner and measuring the RGB parameters with software written in visual basic (VB 6) media. Parameters impacting the extraction efficiency such as pH of the system, the concentration of surfactant, equilibration temperature and time were optimized. Detection limit (DL), relative standard deviation (RSD) and linear range for the proposed method are 0.026, 0.71 and 0.16-6.6 μg mL^-1 respectively. Themethod was successfully applied for the determination of Violet Covasol dye in several water samples, including a water sample containing the dye as a tracer (to investigate subsurface water movement).