Direct aqueous injection LC-ESI/MS/MS analysis of water for 11 chloro- and thiomethyltriazines and metolachlor and its ethanesulfonic and oxanilic acid degradates

A multianalyte method is reported for the determination of atrazine, simazine, propazine, and their respective dealkylated chlorotriazine metabolites; ametryn and prometryn and their respective dealkylated thiomethyltriazine metabolites; and S-metolachlor and its ethanesulfonic and oxanilic acid degradates in deionized, ground, surface, and finished drinking water. Water samples are analyzed using direct aqueous injection (DAI) liquid chromatography-electrospray ionization/mass spectrometry/mass spectrometry (LC-ESI/MS/MS). No preanalysis sample manipulation is required other than transfer of a small portion of sample to an injection vial. The lower limit of the method validation is 0.050 mu g/L (ppb) for all analytes except 2,4-diamino-6-chloro-s-triazine (didealkylatrazine, DDA, or G-28273). For this compound the LLMV is 0.50 mu g/L (ppb). The overall mean procedural recoveries (and percent relative standard deviations) for all water types for all analytes ranged from 95 to 101 % (4.5-11 %). The method validation was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160.