(1,1'-Biphenyl)-2,2'-disulfonic acid, 4,4'-bis((4,5-dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-1H-pyrazol-4-yl)azo)-, tetrasodium salt (1,1'-Biphenyl)-2,2'-disulfonic acid,4,4'-bis((4,5-dihydro-3-methyl-5-oxo-1-(4'-sulfophenyl)-1H-pyrazol-4-yl)azo)-, tetrasodium salt 72927-70-9 EINECS 277-018-2 Tetrasodium 4,4'-bis((4,5-dihydro-3-methyl-5-oxo-1-(4-sulphonatophenyl)-1H-pyrazol-4-yl)azo)(1,1'-biphenyl)-2,2'-disulphonate