Dyes can be found in the printing ink in magazines, and also in plastics, textiles, leather, diesel fuel, and tattoo color. Most of these synthetic colors are based on aromatic ring structures containing heteroatoms, and tend to have a high potential for causing cancer. As a result, they are not intended for use in food coloring. Beginning in 2003, there have been several incidents of chili powder contaminated with the dye Sudan I, intentionally added to make its color more appealing. HPLC can be used for the analysis of spice mixtures to determine if they have been adulterated.

Technical Article:
Colors of the World: Fast Separation of Dyes with Ascentis Express