Ultramicro Method for Determination of Iron in Serum with the Graphite Furnace

Abstract

An ultramicro method is described for determining iron in 50 µl of serum. Hot trichloroacetic acid is used to remove protein and hemoglobin iron, and atomic absorption analysis of 10 µl of the supernatant fluid is carried out with use of a graphite furnace and a specially grooved graphite tube. Results correlate well with those obtained by a conventional flame atomic absorption method for iron that requires a 1-ml sample of serum. A standard graphite tube can be used if the trichloroacetic acid extract is first diluted with water, but we rejected this procedure because of the extra time and effort involved and because of the increased problem of artifactual contamination with iron. When serum was analyzed with no pretreatment, results were higher, probably because of hemoglobin iron present in serum, even serum with no visible hemolysis.