The tandem analytical method of flow injection diode array spectrophotometry and flame atomic absorption spectrometry (FI-DAD(vis)-FAAS) in iron speciation studies using 1,10-phenanthroline complexes

The article presents the new analytical method of determination of the content of selected iron forms in soil and sediment extracts. The presented tandem analytical system uses the molecular and atomic absorption and works in the flow injection mode. The system is equipped with two detectors: the spectrophotometric detector of diode array and the atomic absorption spectrometer. The new analytical system allows for the determinations of the content of ionic iron forms: Fe(II) and Fe(III), as well as the content of non-ionic forms complexed in the extracts of soil and sediment solid samples. The determination limits of 0.2, 0.9 and 0.9 μg mL− 1 were obtained, for Fe(II), Fe(III) and for iron in acid leachable fraction in solid sample extracts respectively, and the precision of determinations fell within the range of 1.8% - 2.4%. The developed and optimised analytical method was applied in the studies of iron speciation in the acid leachable fraction of sediments and soils of different origin.