Indigo carmine

Indigo carmine is a blue, anionic indigoid dye consisting of an indigo dimer with sodium salts of sulfonic acids at positions 5 and 5'. This compound has been used as a tissue stain, pH indicator (Blue (at pH11.5) to yellow (at pH14.0)) and tool for the determination of hypochlorite in solutions. It is also applied in detecting microorganisms, treating amyloidosis, in medical devices and drug delivery systems. It can be used as a contrast stain for plasma when red nuclear stains are used. It is widely used in food and cosmetic industry (beverages, chewing gums, candies, drinks, frozen products, sweetener, tablets, sunscreen, skin and hair products) and as an additive or as a dye for cationic cotton fabrics, filters, display devices, inks, toners, paints, photographic material and toys. Spectral Data: Absorption λmax 608nm.