title: Solid-phase extraction of pesticides from water: possible interferences from dissolved organic material.
abstract: A multiresidue analysis for trifluralin, simazine, atrazine, propazine, diazinon, parathion-methyl, alachlor, malathion, parathion, chlorpyrifos, pendimethalin, methidathion, and DEF in water that utilizes liquid-solid extraction (LSE) with octadecyl-bonded silica cartridges (C18BSCs) followed by gas chromatography/mass spectrometric analysis was developed. Recoveries of most pesticides were greater than 80% with C18BSCs from fortified water at concentration levels from about 1 to 500 ppb. Recoveries with C18BSCs, from an optically adjusted humic acid solution (10 ppm dissolved organic carbon) made to simulate a natural water with a high dissolved organic content, ranged from 29 to 153% and in general were lower than recoveries obtained from pure water. 14C-Labeled diazinon and parathion were recovered from the humic acid solution at levels of 57 and 68%, respectively, with C18BSCs; the remainder of the labeled pesticides was found in the cartridge eluents. Partition coefficients with human acid were calculated based on recovery of 14C-labeled pesticides from the C18BSCs.
authors.affiliation: Natural Resources Institute, Environmental Chemistry Laboratory, USDA-ARS, Beltsville, Maryland 20705.
authors.forename: W E
authors.initials: WE
authors.lastname: Johnson
authors.forename: N J
authors.initials: NJ
authors.lastname: Fendinger
authors.forename: J R
authors.initials: JR
authors.lastname: Plimmer
mesh_terms: D007202:Indicators and Reagents; D010573:Pesticide Residues / Q000032:analysis; D010575:Pesticides / Q000032:analysis* / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007202:Indicators and Reagents; D010573:Pesticide Residues; D010575:Pesticides; D014874:Water Pollutants, Chemical