Simultaneous determination of copper and iron in a single aliquot of serum.

Copper and iron may be sequentially measured in a single aliquot of a protein-free filtrate by use of bis(1 -piperidylthiocarbonyl) disulfide and disodium 3(2pyridyl) -5,6-bis(4-phenylsulfonic acid) -1, 2,4-triazine (also known as ferrozine). Recovery studies showed excellent results for both metals in various concentrations. Copper interference has been obviated by use of thiourea in mercaptoacetic acid. Simultaneous equations are not needed in calculating results and high-reading blanks are eliminated. Comparative results are given with methods in which each metal was measured singly.