SPECIATION OF TRACE-METALS IN POND WATER AS STUDIED BY LIQUID-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

An on-line separation-detection system, liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS), has been d eveloped and applied to the study on speciation of trace metals in pon d water. First, the total concentrations of dissolved metal ions in po nd water were determined by ICP-MS after chelating resin preconcentrat ion. Then, pond water was preconcentrated by ultrafiltration using a f ilter with a molecular weight permeation limit of 10000, providing siz e 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, sequ entially. In consequence, large organic molecules with the molecular w eight of greater than or equal to 300000 and 10000-50000 could be obse rved. 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 from th eir concentrations as determined by the flow injection method.