DETERMINATION OF SIZE AND ELEMENT COMPOSITION DISTRIBUTIONS OF COMPLEX COLLOIDS BY SEDIMENTATION FIELD-FLOW FRACTIONATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

Sedimentation field-flow fractionation (SdFFF) and inductively coupled plasma mass spectrometry (ICP-MS) have been directly combined and the resulting SdFFF-ICP-MS instrument can be used to produce element base d size distributions of colloidal samples. Using appropriate tracer el ements the size distributions of specific components can be picked out from a complex mixture. Changes in chemical composition of mixtures a s a function of particle size can be readily monitored by plotting app ropriate element atomic ratio distributions. These applications have b een illustrated using data obtained with samples of the clay minerals kaolinite and illite and a natural suspended particulate matter from t he Darling River (Australia).