2,7-Naphthalenedisulfonic acid, 3-[[4-(ethylamino)phenyl]azo]-4,5-dihydroxy-, disodium salt 2,7-Naphthalenedisulfonic acid, 3-[[p-(ethylamino)phenyl]azo]-4,5-dihydroxy-, disodium salt 5850-55-5 Ampho magenta C.I. 16590 NSC16209