2-Naphthalenesulfonic acid, 5(or 8)-amino-8(or 5)-(phenylazo)-, monosodium salt 4-(Phenylazo)-1-amino-6(or 7)-naphthalenesulfonic acid, sodium salt 67969-74-8 EINECS 267-979-6 Sodium (5or8)-amino-(8or5)-(phenylazo)naphthalene-2-sulphonate