Improved GC-MS/MS Method for Determination of Atrazine and Its Chlorinated Metabolites in Forage Plants - Laboratory and Field Experiments

Analytical procedures using gas chromatography–ion trap tandem mass spectrometry (GC-MS/MS) were developed to analyze atrazine (ATR) and its dealkylated metabolites in four forage species (switchgrass, tall fescue, smooth bromegrass, and orchardgrass). Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were extracted with methanol (CH3OH) followed by liquid–liquid extraction and partitioning into chloroform, with additional cleanup by C18 solid-phase extraction (SPE). Through the optimization of ionization conditions and ion storage voltages, the background noise of product ion spectra (MS/MS) was reduced dramatically, providing sub-mg/kg detection limits. Mean recoveries of ATR, DEA, and DIA were 94.3, 105.6, and 113.1%, respectively. The estimated limit of detection (LOD) was 0.6 mg/kg for ATR, 1.3 mg/kg for DEA, and 0.3 mg/kg for DIA. These LODs were one to two orders of magnitude lower than those reported for other GC-MS, GCMS/MS, high pressure liquid chromatography (HPLC)-UV, or HPLC-MS/MS Received 12 December 2005, Accepted 5 October 2006 Address correspondence to Chung-Ho Lin, School of Natural Resources, 203 Anheuser-Busch Natural Resources Building, University of Missouri, Columbia, MO 65211, USA. E-mail: [email protected] Communications in Soil Science and Plant Analysis, 38: 1753–1773, 2007 Copyright # Taylor & Francis Group, LLC ISSN 0010-3624 print/1532-2416 online DOI: 10.1080/00103620701435522