Spectrophotometric Determination of Azorubine and Ponceau 4R in Pharmaceutical Preparations Using Micellar Extraction

We compared the capabilities of extraction systems based on polyoxyethylated alkylphenols Triton X-100 and OP-10 for extracting synthetic food dyes Azorubine and Ponceau 4R in different phase separation modes: cloud-point temperature and salting-out with sodium sulfate. The effects of temperature, pH, surfactant, and electrolyte concentrations on the physicochemical characteristics of the micellar phase and the rate for reaching phase equilibrium are studied. A simple and effective extraction procedure with salting-out is proposed. The optimal conditions for the maximum extraction of the dyes (R > 98%) were determined in various modes: at the cloud point for Azorubine and upon salting-out for Ponceau 4R. Procedures have been developed for the spectrophotometric determination of analytes in syrups and lozenges with micellar-extraction preconcentration.