Analytical Method for the Determination of Atrazine and Its Dealkylated Chlorotriazine Metabolites in Water Using SPE Sample Preparation and GC-MSD Analysis

A method is reported for the determination of atrazine and its dealkylated chlorotriazine metabolites in ground, surface, and deionized water. Water samples are adjusted to pH 3−4 prior to loading onto two SPE cartridges in series: C-18 and C-18/cation exchange mixed-mode polymeric phases. The analytes are eluted from each of the two cartridges separately, and the pooled and concentrated fraction is analyzed using gas chromatography−mass selective detection in the selected ion monitoring mode. The lower limit of method validation is 0.10 μg/L (ppb) for 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (G-30033, deethylatrazine), 2-amino-4-chloro-6-(ethylamino)-s-triazine (G-28279, deisopropylatrazine), and 2,4-diamino-6-chloro-s-triazine (G-28273, didealkyatrazine). The overall mean procedural recoveries (and standard deviations) are 96 (6.9), 96 (5.5), 95 (6.8), and 100% (10%) for atrazine, G-30033, G-28279, and G-28273, respectively (n = 49). The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160. The reported procedure accounts for residues of G-28273 in water. Keywords: Atrazine; dealkylated chlorotriazine metabolites; diaminochlorotriazine (DACT); deethyldeisopropylatrazine (DEDIA); didealkylatrazine (DDA); G-28273; ground water; surface water; Good Laboratory Practices (GLP)