2,4-Diamino-5-((2-hydroxy-5-nitrophenyl)azo)benzenesulfonic acid sodium salt Benzenesulfonic acid, 2,4-diamino-5-((o-hydroxy-5-nitrophenyl)azo)-, sodium salt DB5910000 Sodium 2-hydroxy-5-nitro-2',4'-diaminoazobenzene-5'-sulfonate