disodium 5-[[4-[(5-sulphonato-1-naphthyl)azo]-1-naphthyl]azo]-8-(p-tolylamino)naphthalene-1-sulphonate Acid black 21 (C.I. 26405) 4-[(4-Methylphenyl)amino]-4'-[(5-sodiosulfo-1-naphthalenyl)azo][1,1'-azobisnaphthalene]-5-sulfonic acid sodium salt C.I.26405 COOMASSIE FAST BLACK G disodium,8-(4-methylanilino)-5-[[4-[(5-sulfonatonaphthalen-1-yl)diazenyl]naphthalen-1-yl]diazenyl]naphthalene-1-sulfonate Acid Black 21 C.I.Acid Black 21:C.I.26405