1. Programme INTERREG III A : STARDUST
VLIZ
Spatial and Temporal Assessment of high Resolution Depth profiles Using novel Sampling Technologies
Iron speciation in porewaters using the DET technique
Brussels, September 24, 2004

2. Simple method for Fe speciation
Fe 2+ forms a coloured complex with ferrozine
Measure spectrophometrically
Reduction of Fe 3+ with NH2OH.HCl
Measure total Fe spectrophometrically
Concentrations of Fe in porewater are sufficiently high to measure Fe in DET gels (20µl) spectrophometrically after dilution to 1 ml

3. Leie, Menen, Fe in porewaters DET technique
Up to 20% of Fe present as dissolved Fe3+ complexes

4. North Sea, station 130 (Oostende)
Up to 40% present as Fe3+ in both handling circumstances
Presence of dissolved Fe3+ complexes (colloidial oxyhydroxides) may partially explain differences between DGT and DET results