170020-61-8 2,7-Naphthalenedisulfonic acid, 5-((2,3-dichlorobenzoyl)amino)-3-((4-((8-((2,4-dichlorobenzoyl)amino)-1-hydroxy-3,6-disulfo-2-naphthalenyl)azo)phenyl)azo)-4-hydroxy-, tetrasodium salt FP-21399