tetrasodium 3,3-[(3,3-diethoxy[1,1-biphenyl]-4,4-diyl)bis(azo)]bis[5-(benzoylamino)-4-hydroxynaphthalene-2,7-disulphonate];3,3-[(3,3-Diethoxy[1,1-biphenyl]-4,4-diyl)bis(azo)]bis[5-(benzoylamino)-4-hydroxy-2,7-naphthalenedisulfonic acid]tetrasodium salt