Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2000
Publication Date: N/A
Technical Abstract: Field studies are underway that focus on quantifying the impacts of midwestern farming practices on surface and groundwater quality. The growing popularity of low-use rate herbicides for weed control in corn and soybean results in tighter constraints on monitoring for residues. More sensitive methods of detection are needed to address requirements ranging from regional-scale assessments of contamination to tools for total maximum daily load (TMDL) monitoring. Combining ultraviolet absorption spectroscopy (UV) using a photodiode array (PDA) with mass spectrometry-mass spectrometry (MS/MS) enables the analyst to obtain complementary and confirmational information from a single analytical run. Data generated on both surface water and groundwater samples from agricultural field drainage are presented to illustrate the enhanced sensitivity and specificity of this instrumental approach compared to conventional LC/MS. Examples are given for the triazine, chloroacetamide, sulfonylurea, and imidazolinone families of herbicides as well as for several of their soil metabolites and degradates.