DETERMINATION OF HEAVY-METAL INTERACTIONS WITH DISSOLVED ORGANIC MATERIALS IN NATURAL AQUATIC SYSTEMS BY COUPLING A HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY SYSTEM WITH AN INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETER

A high-performance liquid chromatographic (HPLC) system with a size exclusion column is coupled with an inductively coupled plasma mass spectrometer (ICP-MS) for the determination of interactions between heavy metals and different fractions of dissolved organic matter in natural aquatic systems. Direct coupling is applied to get specific distribution patterns of the heavy metal complexes, and on-line isotope dilution mass spectrometry is performed to quantify heavy metals accurately in different organic fractions. With respect to the separation properties of a size exclusion column by molecular size, different distribution patterns could be found for the heavy metals depending on the type of aquatic system. Different distribution patterns in the various fractions of dissolved organic material (preferably of humic substances) could also be observed for the metals in the same natural water sample. In addition, a high-resolution ICP-MS is applied for the first time as an element-specific detector in connection with a HPLC system which also allow interference-free detection of iron species.