SCREENING A SELECTIVE CHELATOR PAIR FOR SIMULTANEOUS DETERMINATION OFIRON(II) AND IRON(III)

Direct determination of Fe(II) and Fe(III) is a fundamental technology for environmental Fe chemistry research. The key to accurate determin ation of Fe(II) and Fe(III) in soil, water, and plant samples is to st abilize Fe oxidation states during Fe extraction and analysis, but the goal has only been partially achieved in previous research. In this r esearch, an approach to stabilizing the original oxidation states of F e during extraction and analysis was studied. The following sequential procedures were conducted: computer simulation -->colorimetric tests --> Fe(III) reduction resistance tests --> metal interference tests -- > sensitivity tests --> determination of optimal pH for Fe extraction. Results indicated that EDTA (ethylenediamine-N,N,N'N'-tetraacetate, d isodium salt) and BPDS (bathophenanthroline disulfonate, disodium salt ) were the most effective chelator pair with which to stabilize Fe oxi dation states and that they may allow accurate, simultaneous determina tion of Fe(II) and Fe(III).