PARTICLE BEAM LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY OF NATIONAL PESTICIDE SURVEY ANALYTES

The U.S. Environmental Protection Agency (US EPA) lists 126 polar, water-soluble compounds in the National Pesticide Survey (NPS) because of their potential for contaminating ground water. From this list, approximately 100 compounds were analyzed by particle beam liquid chromatography/mass spectrometry (PB/LC/MS). The fragmentation patterns of the electron impact (EI) spectra were generally comparable to reference EI spectra and were useful for analyte confirmations. A study of four different commercial nebulizers was performed to assess the effect on chromatographic integrity. In addition to the use of PB/LC/MS as a qualitative confirmation tool, its use as a selective LC detector was evaluated. Forty three of the NPS analytes showed sufficient sensitivity for detection of and spectrum generation from 100 ng or less. Using published concentration and cleanup methods, this sensitivity is sufficient for confirming the presence of these analytes in ground water at the 0.1 ppb level.