Molecular characterisation of the bonding of herbicide metabolites to humic acid

First firm evidence is reported for the binding of metabolites of methabenzthiazuron to a specific entity in humic acid. Humic acid being a complex, non-unique chemical substance, the elucidation of binding to a specific site was made plausible by NMR spectra with the interpretation supported by quantum chemical calculations. This illustrates the necessity and the power of current multi-technique approaches to study truly complex systems.