Validation of the Methodology to Determine Synthetic Dyes in Foods and Beverages by HPLC

Synthetic dyes are added to foods due to the many changes which alter or destroy the natural colors of the products during processing and/or storage, and principally to increase the acceptance of the product, by the customer. Synthetic dyes show several advantages over natural pigments. The lack of adequate analytical methodology has made it difficult to control the levels of coloring agents in foods. Also, there is no methodology capable of responding to the size and the demand for such analyses by the industrial sector, in several types of food. This work, proposed and validated a methodology for the simultaneous determination of the eight synthetic colors: Sunset yellow [E-110], yellow n°5 [E-102], bordeaux S [E-123], red n°40 [E-129], red n°17 [E-124], red n°3 [E-127], brilliant blue [E-133] and indigo carmin [E-132], allowed in foods in Brazil, using the technique of high performance liquid chromatography (HPLC). The dye was extracted with warm water (40 to 50°C), the solution was centrifuged, and finally filtered through fluoropore filter FHLP 01300 of 0.5 μm. It was then injected into the chromatograph. In the chromatographic process, the use of the column ODS-2 and the mobile phases H2O/MeOH (70 : 30), plus 0.08 mol/L of ammonia acetate for conditioning and H2O/MeOH (70 : 30) for the run, allowed for the elution of the synthetic dyes in 20 min, plus 12.5 min to equilibrate the column before another injection. The detection and recovery limits determined were respectively: 0.5 &μ/mL and 96.3% for indigo carmin; 1.30 &μ/mL and 98.2% for brilliant blue; 1.02 &μ/mL and 102% for bordeaux S; 0.57 &μ/mL and 96.8% for red n°17; 1.10 &μ/mL and 100.3% for red n°40; 0.51 &μ/mL and 96% for red n°3; 0.70 &μ/mL and 99.7% for yellow n°5; 1.83 &μ/mL and 98.9% for sunset yellow. The test for repeatability showed coefficients of variation below 5% for the colorings. The proposed methodology, validated here, presents efficiency, versatility, speed, and simplicity.