Extraction and spectrophotometric determination of copper(II) with S,S-bis(2-aminophenyl)oxalate.

A new selective reagent, S,S'-bis(2-aminophenyl)oxalate (H2L), for the extractive spectrophotometric determination of copper has been prepared. The ligand, H2L, forms a 1:1 complex with copper(II) in methanol. The molar absorptivity of Cu(II)-S,S'-bis(2-aminophenyl)oxalate complex in methanol is 5365 M(-1) cm(-1) at 504 nm. The method has been applied for the determination of copper in pharmaceutical formulations, environmental and foodstuff samples.