Sudan III  (Synonyms: Sudan Red III; Tetrazobenzene-β-naphthol; 111440 Red)

Sudan III is a hydrophobic bisazo dye^[1].

Sudan III changes its color from orange to blue against a small volume of sulfuric acid, and the acetonitrile solution of Sudan III is the most suitable for observing the color-change phenomenon. H-NMR and UV-Vis spectroscopic studies show that the color-change mechanism of Sudan III against sulfuric acid is due to the protonation of the dye by sulfuric acid^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

352.40

C₂₂H₁₆N₄O

85-86-9

Solid

Brown to red

OC1=CC=C2C=CC=CC2=C1/N=N/C3=CC=C(/N=N/C4=CC=CC=C4)C=C3

Room temperature in continental US; may vary elsewhere.

4°C, protect from light

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (protect from light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Sakurai T, et al. Color Change of Sudan III against Concentrated Sulfuric Acid in Acetonitrile and Quantification for a Small Amount of Concentrated Sulfuric Acid. Anal Sci. 2016;32(2):129-33.  [Content Brief]