Abstract: | The characterization of refractory organic substances (ROS) is very complicated because of their heterogeneous structure. Size-exclusion chromatography with continuous detection of dissolved nitrogen (LC-DN), dissolved organic carbon (LC-DOC), and UV-absorbance (LC-UV) is a very useful analytical tool for the characterization of changes of ROS in natural aquatic systems and in technological treatment. The effect of natural, oxidative, and biochemical processes on formation and removal of ROS is described. Additionally the role of hydrolysable carbohydrates in the composition of ROS is presented. |