Acid red 88 is an azo dye. Due to its intense colour, solid samples appear almost black. It is used to dye cotton textiles red.[1] A closely related acid dye is Acid Red 13.
^Song, Ya-Li; Li, Ji-Tai; Chen, Hua (2009). "Degradation of C.I. Acid Red 88 aqueous solution by combination of Fenton's reagent and ultrasound irradiation". J. Chem. Technol. Biotechnol.84 (4): 578–583. doi:10.1002/jctb.2083.