trisodium 5-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-4-hydroxy-3-[(2-hydroxy-3-nitro-5-sulphonatophenyl)azo]naphthalene-2,7-disulphonate

5-[[(4,5-Dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol)-4-yl]azo]-4-hydroxy-3-[(2-hydroxy-3-nitro-5-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt