2,7-Naphthalenedisulfonic acid, 3-((2-arsonophenyl)azo)-4,5-dihydroxy- 520-10-5 AI3-52540 Arsenazo I EINECS 208-285-5 Trisodium 2-(-hydrogen arsonatophenylazo)-1,8-dihydroxynaphthalene-3,6-disulphonate