DIRECT DETERMINATION OF SERUM IRON BY EXT RACTION-DERIVATIVE SPECTROPHOTOMETRY

A simple, rapid and reproductible method by extraction-derivative spec trophotometry, without the classic deproteination step, is proposed fo r the direct determination of serum iron, This method is based on the integration of liquid-liquid separation and reaction at pH = 5.0 of ir on with (4-phenyl-2-pyridinyl)-5-phenyl-1,2,4 triazine (PPT) and 2,4,6 -trinitro-phenol (picric acid) in dichloroethane. The reaction and the extraction are quantitative, being the proteins free of iron. A phase separator (Whatman IFS) was also used, which permits the separation o f organic phase containing the analyte, as the iron(II)-PPT-picrate co mplex. The proteins were retained quantitatively. The iron content wer e measured by first-derivative absorption spectrum, using Delta lambda = 20 nm. As the method is free from cation interferences it was succe ssfully applied to the determination of iron in human serum.