4-(4-((2,5-Dimethoxy-4-((2-(sulphooxy)ethyl)sulphonyl)phenyl)azo)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulphonic acid, sodium salt 62121-76-0 Benzenesulfonic acid, 4-(4-((2,5-dimethoxy-4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)-, sodium salt EINECS 263-418-4