A simple flow injection system with bead injection for trace iron determination

A simple and low cost flow injection (FI) system with bead injection (BI) was developed for determination of low concentration (μmol l−1) of iron in water samples. Chelex-100 chelating resin beads, trapped in a jet ring cell, were employed. The intensity of red complex of 1,10-phenanthroline with Fe2+ was monitored using colorimetric detector with a LED green light source. Amount of total Fe (Fe2+ and Fe3+) and Fe2+ can be evaluated by with and without reduction of Fe3+ using ascorbic acid. Lowest detectable levels of Fe2+ were 0.90 and 0.45 μmol l−1 for sample loading time of 3 and 5 min, respectively. Working range was up to 3.90 μmol l−1 using 0.3% w/v 1, 10-phenanthroline. Percent recoveries of spiked water samples (0.90–2.33 μmol l−1 of Fe2+) were 100–110%.