Hexanoic acid, 6-[[2-[[5-[[2,7-dihydro-3-methyl-2,7-dioxo-1-(3-sulfobenzoyl)-3H-naphtho[1,2,3-de]quinolin-6-yl]amino]-2,4-disulfophenyl]amino]-2-oxoethyl]amino]-, ammonium sodium salt (1:?:?)