Analytical Method for the Determination of Atrazine and Its Dealkylated Chlorotriazine Metabolites in Urine by Gas Chromatography/Mass Selective Detection

A multiresidue method is reported for the determination of atrazine and its chloro dealkylated metabolites in urine. Urine samples were subjected to a protein precipitation procedure followed by further purification using strong anion exchange and silica solid-phase extraction columns. Final analysis was accomplished using gas chromatography/mass selective detection in the selected ion monitoring mode. The limits of detection were 0.050 ng injected for 2,4-diamino-6-chloro-s-triazine (G-28273) and 0.025 ng injected for 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (G-30033), and 2-amino-4-chloro-6-(ethylamino)-s-triazine (G-28279). The limits of quantification were 1.0 ppb for atrazine and G-30033 and 2.0 ppb for G-28279 and G-28273. The mean procedural recoveries obtained during the method validation were 115, 113, 112, and 97% and the standard deviations were 10.6, 10.2, 9.5, and 16.1% for atrazine, G-30033, G-28279, and G-28273, respectively. Additional recovery data were obtained during a worker exposure study and during an outside ruggedness trial. All studies were conducted under U.S. EPA FIFRA Good Laboratory Practice Standards 40 CFR 160.