Speciation of Trace Metals in Pond Water as Studied by Liquid Chromatography/Inductively Coupled Plasma Mass Spectorometry

An on-line separation-detection system, liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS), has been developed and applied to the study on speciation of trace metals in pond water. First, the total concentrations of dissolved metal ions in pond water were determined by ICP-MS after chelating resin preconcentration. Then, pond water was preconcentrated by ultrafiltration using a filter with a molecular weight permeation limit of 10000, providing size exclusion chromatography. Large organic molecules which had combined with trace metals in the preconcentrated samples were separated with a gel filtration column and detected by UV absorption and ICP-MS, sequentially. In consequence, large organic molecules with the molecular weight of ≥300000 and 10000—50000 could be observed. A large number of trace metals (41 elements) were found in those organic molecules. Furthermore, the percentages of metal ions in the forms of large organic molecule–metal complexes were estimated f...