The study of the interactions between heavy metals with sulfonylurea herbicides using ACE

The affinity capillary electrophoresis method was used in the study of interactions between heavy metals (Pb, Mn, La, Cd, and Ni) and the sulfonylurea herbicides (thifensulfuron, nicosulfuron and sulfometuron). A buffer of 50 mM acetate (pH 5.85) was employed in the study. The results proved that there are two binding sites in the herbicides when chelating with the heavy metals. Binding constants of the high chelating ability sites between them were in the range of 10(3) to 10(5), and the other were in the range of 10 to 10(3). Thifensulfuron is the most powerful chelator among the three herbicides. Ni is of the weaker chelators, within the herbicides than Pb, Mn, La, and Cd. The binding abilities were proven to be increased with the pH value among the investigated range.