disodium 2,5-dichloro-4-[4,5-dihydro-4-[[2-methoxy-5-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonate;2,5-Dichloro-4-[[4,5-dihydro-4-[[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol]-1-yl]benzenesulfonic acid disodium salt