Application of reducing column for metal speciation by flow injection analysis : Spectrophotometric Determination of Iron(III) and Simultaneous Determination of Iron(II) and Total Iron

Abstract

Iron(III) (3 × 10 −4-5 × 10 −4 M) is determined in a flow-injection system by passage through a Jones reductor mini-column before spectrophotometric detection with 1,10-phenathroline in citrate buffer, pH 5.0. The mid-range precision is < 1.4%, at a sampling rate of 60 h −1. Iron(II) and total iron are determined by splitting the injected sample so that a portion passes through the reductor column and a delay coil before both streams are recombined with the unreduced portion preceding the remainder of the sample to mix with the reagent for spectrophotometric detection. Two peaks are produced for each sample, the first being measure of iron(II), the second of total iron.