IDENTIFICATION OF FENTONS-REAGENT-GENERATED ATRAZINE DEGRADATION PRODUCTS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND MEGAFLOW ELECTROSPRAY-IONIZATION TANDEM MASS-SPECTROMETRY

High-performance liquid chromatography megaflow electrospray tandem mass spectrometry (HPLC/ES-MS/MS) with an on-line radioisotope detector was used to identify [2,4,6-C-14]atrazine degradation products generated by treatment with Fenton's reagent (Fe2+ and H2O2). Fenton's reagent produced dealkylated and/or partially oxidized [2,4,6-C-14]atrazine products in preference to dechlorinated products, Seven major products were identified by collision-induced dissociation spectra: 4-acetamido-2-chloro-6-(isopropylamino)-s-triazine, 4-amino-2-chloro-6(isopropylamino)-s-triazine, 4-acetamido-2-chloro-6-(ethylamino)-s-triazine, 6-amino-2-chloro-4-(ethylamino)-s-triazine, 4-acetamido-6-amino-2-chloro-s-triazine, 2-chloro-4,6-diamino-s-triazine and the first report of 4-acetamido-2-hydroxy-6-(isopropylamino)-s-triazine. HPLC/ES-MS/MS provided a rapid method for identifying a wide range of atrazine transformation products in aqueous samples and obviated the need for fraction collection, extraction, and chemical derivatization of the more polar atrazine products, Furthermore, because analyte retention times in HPLC/UV and HPLC/ES-MS/MS were similar, compound identities determined using the latter could be directly assigned to peaks in UV chromatograms.