Microdetermination of copper with 4-S-benzyl-1-p-chloro-phenyl-5-phenyl-2,4-isodithiobiuret (BPPTB)

4-S-Benzyl-1-p-chloro-phenyl-5-phenyl-2,4-isodithiobiuret (BPPTB) forms bis complex with copper(II). The complex is easily extractable in chloroform. It exhibits a λ_max at 368 nm. The values of the equilibrium constants have been evaluated by different methods. The analytical application of this system has been studied. It was found that copper can easily be separated from large numbers of ions which are generally associated with it. A suitable procedure has been recommended for spectrophotometric microdetermination of copper.