Gradient gel electrophoretic characterization of humic substances and of bound residues of the herbicide bentazon

Radioactive herbicide compounds bound to humic material were separated by sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis (SDS-PAGGE) and detected by autoradiography. SDS-PAGGE could be applied to separate humic substances according to their molecular masses, and to follow their time-dependent polymerisation. Autoradiographic analysis showed that the herbicide bentazon and its methyl and hydroxy derivatives were bound in humic substance fractions of different molecular mass.