2-Naphthalenesulfonic acid, 6-(acetylmethylamino)-4-hydroxy-3-((3-phosphonophenyl)azo)-, monosodium salt 6-(Acetylmethylamino)-4-hydroxy-3-((3-phosphonophenyl)azo)-2-naphthalenesulfonic acid, monosodium salt 68133-28-8 EINECS 268-671-4 Sodium hydrogen 6-(acetylmethylamino)-4-hydroxy-3-((3-phosphonatophenyl)azo)naphthalene-2-sulphonate