title: HPLC-accelerator MS measurement of atrazine metabolites in human urine after dermal exposure.
abstract: Metabolites of atrazine were measured in human urine after dermal exposure using HPLC to separate and identify metabolites and accelerator mass spectrometry (AMS) to quantify them. Ring-labeled [14C]atrazine was applied for 24 h with a dermal patch to human volunteers at low (0.167 mg, 6.45 muCi) and high (1.98 mg, 24.7 muCi) doses. Urine was collected for 7 days. The urine was centrifuged to remove solids, and the supernatant was measured by liquid scintillation counting prior to injection on the HPLC to ensure that < 0.17 Bq (4.5 pCi) was injected on the column. A reversed-phase gradient of 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile became less polar with increasing time and separated the parent compound and major atrazine metabolites over 31 min on an octadecylsilane column. Peaks were identified by coelution with known standards. Elution fractions were collected in 1-min increments; half of each fraction was analyzed by AMS to obtain limits of quantitation of 14 amol. Mercapturate metabolites of atrazine and dealkylated atrazine dominated the early metabolic time points, accounting for approximately 90% of the 14C in the urine. No parent compound was detected. The excreted atrazine metabolites became more polar with increasing time, and an unidentified polar metabolite that was present in all samples became as prevalent as any of the known ring metabolites several days after the dose was delivered. Knowledge of metabolite dynamics is crucial to developing useful assays for monitoring atrazine exposure in agricultural workers.
authors.affiliation: Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94551, USA. buchholz2@llnl.gov
authors.forename: B A
authors.initials: BA
authors.lastname: Buchholz
authors.forename: E
authors.initials: E
authors.lastname: Fultz
authors.forename: K W
authors.initials: KW
authors.lastname: Haack
authors.forename: J S
authors.initials: JS
authors.lastname: Vogel
authors.forename: S D
authors.initials: SD
authors.lastname: Gilman
authors.forename: S J
authors.initials: SJ
authors.lastname: Gee
authors.forename: B D
authors.initials: BD
authors.lastname: Hammock
authors.forename: X
authors.initials: X
authors.lastname: Hui
authors.forename: R C
authors.initials: RC
authors.lastname: Wester
authors.forename: H I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000279:Administration, Cutaneous; D001280:Atrazine / Q000008:administration & dosage / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006540:Herbicides / Q000008:administration & dosage / Q000652:urine*; D006801:Humans; D008956:Models, Chemical; D012867:Skin / Q000378:metabolism*
chemical_list: D006540:Herbicides; D001280:Atrazine