Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 1787-61-7, Whether you call it Eriochrome Black T, 3-Hydroxy-4-[(1-hydroxy-2-naphthalenyl)azo]-7-nitro-1-naphthalenesulfonic Acid Monosodium Salt or Mordant Black 11 you can be assured the Eriochrome Black T products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.