Pesticide Analysis in Southeast Michigan Waters by GC-MS

Dutta, Riaa, Reima Alsareti, Kendra Evans, and Elizabeth Roberts-Kirchhoff

The purpose of this research is to analyze pesticides in river water by gas chromatography-mass spectrometry (GC-MS).  Many pesticides have been identified as endocrine disrupting compounds.  One such pesticide, atrazine, is one of the most widely used pesticides in the United States. Nine pesticides (alachlor, aldrin, atrazine, cyanazine, endosulfan I, endrin, metolachlor, methoxychlor, and pendimethalin) were dissolved in HPLC-grade acetone and analyzed by GC-MS to determine the retention times and the mass spectrum for each.  Different concentrations of atrazine were used to spike various water samples including distilled, tap, and river water to determine if the method is feasible.  The atrazine in the water samples was concentrated by filtering the samples with a C18 solid-phase extraction disk in a glass-filtration apparatus.  The contaminants on the disk were released using a mixture of acetone and n-hexane.  The organic phase was dried with anhydrous sulfate, concentrated with a rotary evaporator and finally evaporated to dryness with a dry-bath incubator with nitrogen gas.  The sample was dissolved in acetone and then analyzed by GC-MS using programs for total-ion and selective-ion monitoring.