A Single Phase System for the Determination of Iron (III) in Biological Materials by Means of 2-thenoyltrifluoracetone

The methods commonly used for the routine determination of iron in serum involve the use of the phenanthrolines which form colored complexed with the iron(III) ion. Iron in biological materials may be in either or both of its two oxidation states; therefore, reduction is required before quantitative complex formation with the phenanthrolines can take place. In a recent thesis submitted to the Marquette Graduate School (23), a colorimetric method for the determination of iron (III) in serum using 2-thenoyltrifluoroacetone (TTA) was described. In this procedure, preliminary wet-ashing of the sample by digestion with concentrated nitric acid and 30 per cent hydrogen peroxide was carried out. This treatment yielded iron in the iron (III) oxidation state, and reduction was not required before formation of a colored complex with TTA. A disadvantage of this method was that the molar absorbancy of the TTA-iron (III) complex at the measured wavelength was only about half that produced by the substituted phenanthroline-iron complexes. In addition, the procedure entailed a time consuming extraction step of iron from an aqueous to an organic phase prior to spectrophotometric determination. The object of this research was to: 1. Seek modifications in the procedure toward increasing the sensitivity of the TTA-iron assay. 2. Develop a single-phase system which would eliminate the extraction step