Serum iron determination.

N IRON REAGENT, 4 ,7-diphenyl-1 , lO-phenanthroline, which has a more desirable sensitivity than other known iron reagents, has been introduced by Case (1), has been used by Smith et at. (2) in the estimation of iron in water, and in serum by Peterson (3) who reported the molar absorbency index of the iron complex of this new reagent as almost three times that of a-a’-dipyridyl or o-phenanthroline. This reagent also has an added advantage in that its iron complex can be separated with isoamyl alcohol from aqueous solutions which contain interfering ions. We have made a comparative study of several serum iron methods, and have obtained lower iron values with the method of Peterson (3) than that of Kitzes et at. (4) or Ramsey (5). Since the methods of Kitzes and Ramsey require larger serum specimens and are time consuming, and the method of Peterson gave lower serum iron values, an investigation was undertaken to develop an improved serum iron method using the more sensitive 4, 7-diphenyl-1 , lO-phenanthroline reagent.