Characterization of a covalent triazine-humic acid conjugate by gas chromatography

The aim of the described method was the characterization of a “atrazine-mercaptopropionic acid” humic acid conjugate, which was required for the calibration of immunoassays to determine bound residues. In order to estimate the amount of bound triazine, an oxidative nucleophilic substitution reaction of the covalently linked “atrazine-mercaptopropionic acid” to a new triazine derivative “atrazine-methoxyethanol” was performed. This cleavage product was quantified by gas chromatography. The conditions for this cleavage procedure were optimized and applied to the “atrazine-mercaptopropionic acid” humic acid conjugate and to a humic acid blank. The amount of bound “atrazine-mercaptopropionic acid” was calculated to 16.6 ± 2.5 μmol triazine per gram humic acid, which is equivalent to 0.39 ± 0.07% atrazine. Received: 7 August 1997 / Accepted: 12 September 1997