2,7-NAPHTHALENEDISULFONIC ACID 4-AMINO-3-[[4-[[[4-[(8-AMINO-1-HYDROXY-5-SULFO-2-NAPHTHALENYL)AZO]PHENYL]AMINO]CARBONYL]PHENYL]AZO]-5-HYDROXY-6-(PHENYLAZO)-,MONOSODIUM SALT