Copper(I) ions are generally unstable in aqueous solution and readily disproportionate to copper(II) and copper(0). In this work, copper(I) is formed and stabilized under aerobic conditions by the addition of glutathione (GSH) which acts as a reducing and complexing agent. The extraction of Cu(I) with heterocyclic bidentate amines such as 2,9-dimethyl-1,10-phenanthroline (dmp), 2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline, and 2,2’-biquinoline has been studied in the presence of GSH.The formation of the Cu(I)-GSH complex in the aqueous solution was confirmed by spectrophotometry under aerobic conditions.Time-course measurements of the absorbance indicated that the Cu(I)-GSH complex retained stability toward re-oxidation by air for at least 6 h in the presence of a 10-fold excess of GSH at pH 5-7.The quantitative extraction of copper(I) was accomplished with 5.0 × 10−4 M dmp in chloroform or 1,2-dichloroethane in the presence of 5.0 × 10−4 M GSH and 0.10 M ClO4− at pH 3-6. The extracted species was found to be Cu(dmp)2ClO4 by the substoichiometric extraction method.
