5-chloro-6-[4,5-dihydro-4-[[2-methoxy-5-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]toluene-3-sulphonic acid, sodium salt

3-Chloro-4-[[4,5-dihydro-4-[[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazole]-1-yl]-5-methylbenzenesulfonic acid/sodium,(1:x) salt