Colorimetric flow-injection analysis of dissolved iron in high DOC waters.
An iron flow-injection analysis system has been optimized for the analysis of iron in waters high in dissolved organic carbon. The method detects either dissolved iron(II) or total dissolved iron with a detection limit of 10 nM, precision of 0.65% at 1 microM, and a dynamic range of four orders of magnitude. There are minimal interferences (< 1%) from other metals at environmental concentrations. The iron(II) method measures iron(II) in the presence of excess iron(III) with less than 1% interference. When used with pre-acidified samples, the total dissolved iron method agrees well with electrothermal atomic absorption spectrometry for a variety of natural waters with a range of dissolved organic carbon (3-36 mg C/L) and iron (1-28 microM) concentrations. When used with samples at their ambient pH, the total dissolved iron method detects dissolved iron, but not colloidal iron (size fraction 0.05-0.45 micron).
Pullin
M J
MJ
Department of Chemistry and Water Resources Research Institute, Kent State University, Kent, OH 44242, USA.
Cabaniss
S E
SE
D002244:Carbon / Q000737:chemistry; D003124:Colorimetry / Q000379:methods*; D003300:Copper / Q000737:chemistry; D005290:Ferric Compounds / Q000032:analysis; D005296:Ferrous Compounds / Q000032:analysis; D005297:Ferrozine / Q000737:chemistry; D017022:Flow Injection Analysis; D007501:Iron / Q000032:analysis*; D007502:Iron Chelating Agents / Q000737:chemistry; D018625:Microscopy, Atomic Force; D009930:Organic Chemicals / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis*
D005290:Ferric Compounds; D005296:Ferrous Compounds; D007502:Iron Chelating Agents; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D005297:Ferrozine; D002244:Carbon; D003300:Copper; D007501:Iron