Determination of continuous size and trace element distribution of colloidal material in natural water by on-line coupling of flow field-flow fractionation with ICPMS

The coupled technique here presented utilizes the size-separating capabilities of now field-now fractionation (FlFFF) and the high-sensitivity, multielement detection capabilities of inductively coupled plasma mass spectrometry (ICPMS). The system enables determinations of colloidal size and element distributions for 28 elements (including carbon) in natural waters. To cope with the low concentrations often found for colloids and trace elements in natural waters, the conventional FlFFF system has been modified to include an on-channel preconcentration procedure allowing injection of up to 50 mL of sample. The performance of the FlFFF-ICPMS system is further evaluated in terms of reproducibility and detection limits. The size distributions of six selected elements are given, and different colloidal distributions for the elements are discussed.