钍试剂 ;1-(2-胂酸苯偶氮)-2-萘酚-3,6-二磺酸二钠盐,2-(2-羟基-3,6-二磺酸-1-萘基偶氮)苯砷2-[(2-Hydroxy-3,6-disulfo-1-naphthyl)azo]benzenearsonic Acid Disodium Salt Aspan Disodium 1-(2-Arsonophenylazo)-2-naphthol-3,6-disulfonate Thoron 1-(2-Arsonophenylazo)-2-naphthol-3,6-disulfonic