Sudan III

Sudan III is a lysochrome (fat-soluble dye) diazo dye. It is structurally related to azobenzene. Sudan III is a lysochrome (fat-soluble dye) diazo dye. It is structurally related to azobenzene. It is used to color nonpolar substances such as oils, fats, waxes, greases, various hydrocarbon products, and acrylic emulsions. Its main use is as a fuel dye in the United States of America mandated by the IRS to distinguish low-taxed heating oil from automotive diesel fuel, and by the EPA to mark fuels with higher sulfur content; it is a replacement for Solvent Red 26 with better solubility in hydrocarbons. The concentration required by IRS is a spectral equivalent of 3.9 pounds per 1000 barrels, or 11.13 mg/l, of Solvent Red 26 in solid form; the concentrations required by EPA are roughly 5 times lower. Sudan III is a dye used for Sudan staining. Similar dyes include Oil Red O, Sudan IV, and Sudan Black B. They are used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. It has the appearance of reddish brown crystals and a maximum absorption at 507(304) nm. Its other names are D&C Red17, Sudan Red BK, Fat Ponceau G, Cerasin Red, C.I. 26100, Solvent Red 23, Sudan Red, Sudan Red III, Sudan V, Sudan Red B, Sudan G, Scarlet B, and Tony Red. Sudan I, Sudan III, and Sudan IV have been classified as category 3 carcinogens by the International Agency for Research on Cancer. Its risk and safety phrases are S22-S24/S25. Sudan III is harmful if inhaled or swallowed, and can be absorbed through skin. MSDS rated a contact severity of 3, and cannot be made non-poisonous. Inhalation can cause intoxication and eye contact can lead to blurred vision and potentially blindness. The toxic effects exerted upon nervous system, particularly the optic nerve. Once absorbed into the body, it is very slowly eliminated. Symptoms of overexposure may include headache, drowsiness, nausea, vomiting, blurred vision, blindness, coma, and death. Toxicology test: Rat (oral) LD50: 5628 mg/kg.