Photometric determination of copper in iron and steel with diethyldithiocarbamate

A method is described for the direct photome tric determination of copper in steel and Iron .. An 0.1-~o 0.~5-gr.am sal~lple is dissolved in d.ilut~d nitric acid, and a sulfuric-phosphonc-perchlonc aCld mixture IS added. The solutIOn IS evaporated to fumes of sulfuric acid, diluted, and the sodium salt of dimethylglyoxime or ethylenediaminetetraacetic acid added as a comp,Iexing reagent. The copper diethyldithiocarbamate complex is then formed, and extracted With butyl acetate. The butyl acetate extract is washed with diluted sulfuric acid, and the absorbancy of the copper complex is measured at 560 to 600 millimicrons. An accuracy of about 0.005 percent of copper or better is indicated for steels containing 0.05 to 0.25 percent of copper, and of about 0.001 percent of copper for steels containing less than 0.05 percent of copper.