N-[5-[(2-Hydroxy-1-naphthalenyl)azo]-2-[[4'-[(1-hydroxy-4-sodiosulfo-2-naphthalenyl)azo]-3,3'-dimethyl[1,1'-biphenyl]-4-yl]azo]phenyl]oxamidic acid sodium salt
N-[5-[(2-Hydroxy-1-naphthalenyl)azo]-2-[[4'-[(1-hydroxy-4-sodiosulfo-2-naphthalenyl)azo]-3,3'-dimethyl[1,1'-biphenyl]-4-yl]azo]phenyl]oxamidic acid sodium salt