Ammonitun phenyldithiocarbamate and ammonium phenylhydrazine-dithiocarbamate have been found to be suitable reagents for cupric ions.Their 0.05% aqueous solutions give with cupric ions dark brown precipitate or coloration.Limit of identification of both reagents is 0.3 γ (concentration limit,1:166,000),when tests are performed on spot plate.Bismuth,cobaltous,nickelous,mercurous and silver ions interfere.Among them,Co⁺⁺ and Ni⁺⁺ heavily mask the reaction of Cu⁺⁺.But the chelates of Ni⁺⁺and Co⁺⁺can be separated by extraction with CCI;or CHCl₃,in which they are soluble,while the Cu⁺⁺ chelate is insoluble.