2-Naphthalenesulfonic acid, 7-amino-4-hydroxy-3-(phenylazo)-, monosodium salt 6300-24-9 7-Amino-4-hydroxy-3-(phenylazo)-2-naphthalenesulfonic acid, sodium salt EINECS 228-584-4 NSC 45553 Sodium 7-amino-4-hydroxy-3-(phenylazo)naphthalene-2-sulphonate