Food Blue 1:1

with strong sulfuric acid or low concentration fuming sulfuric acid sulphonated 3H-indol-3-one,2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-, and then into aluminum salt deposit color.

green light blue. Blue fine powder, odourless. Hardly soluble in water, oil and most solvent, but can be scattered, mixed with water, oil liquid and solid powder. Resistance to light sex, heat resistance, the salt resistance equal ratio of use 3H-indol-3-one,2-(1,3-dihydro-3-oxo-2H-indol-2-ylidene)-1,2-dihydro-. This product is suitable for oil products, powder of solid and colloid water-soluble colorants are difficult to use items shading. The product is made of a certain amount of strong HCL, added with a certain volume of two potassium hydrogen sulfate solution diluted, the maximum absorption wavelength for 612 + 2 nm.