1,4,6-Anthracenetrisulfonicacid,5-amino-8-[[4-[2-[4-[[(2,3-dichloro-6-quinoxalinyl)carbonyl]amino]-2-sulfophenyl]ethenyl]-3-sulfophenyl]amino]-9,10-dihydro-9,10-dioxo-,sodium salt (1:5)