Capillary zone electrophoretic studies on Norwegian surface water natural organic matter

Capillary tone electrophoresis (CZE) is a useful tool for the analysis of t he electrophoretic behavior of anionic polyelectrolytes like humic substanc es. CZE was used to compare natural organic matter (NOM) with high ash cont ent obtained by reverse osmosis (RO) and low temperature, low pressure evap oration (Ev,) from different Norwegian surface water sources. The quantitat ive relation between the resulting electrophoretic signals (peak height and area) and the carbon amount of the injected NOM samples was found linear. The NOM gave homogeneous signals in CZE, with a distribution of the detecti on signals around an average electrophoretic mobility (AEM) corresponding t o the charge density distribution of the NOM, governed by the distribution of their molecular sizes and acidities. Like humic substances, NOM only app ears as anions in capillary electrophoresis (CE), but the high ash content of these samples and the presence of metals strongly influenced their mobil ities at lower pH. CZE could be used as a tool for the rapid evaluation of the average net charge and the molecular radius of the NOM at pH 5.1. (C) 1 999 Elsevier Science Ltd.