Caribbean-Florida Water Science Center
Lake Wales Ridge Groundwater: Target analytes and laboratory methods
The pesticides and pesticide degradates were analyzed using gas chromatography with a nitrogen phosphorous detector (NPD), high-performance liquid chromatography (HPLC) [both UV/VIS and post column derivatization], liquid chromatography/mass spectroscopy (LC/MS) and ion chromatography, and included both standard USEPA methods and FDACS custom methods for selected compounds. Concentrations of organic compounds in spiked samples generally were within about 75 to 105 percent of expected concentration, with the exception of deisopropyl atrazine, which yielded about 50 percent recovery.
Target analytes evaluated quarterly include field measurements, basic water chemistry, nutrients, pesticides and pesticide degradates, and selected trace constituents. Target analytes and the analyzing laboratories are listed in data table 2 (Excel file). Limited reconnaissance sampling has been performed to assess the occurrence of additional simazine degradates (data table 5)
Method detection limits for pesticides, pesticide degradates, and selected target analytes are listed in table 3.