title: Multiresidue analysis of 102 organophosphorus pesticides in produce at parts-per-billion levels using a modified QuEChERS method and gas chromatography with pulsed flame photometric detection.
abstract: A multiresidue method for the analysis of organophosphorus pesticides in fresh produce at levels down to 1.0 microg/kg (ppb) has been developed using a modification of the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. The procedure entails extraction of pesticides from the sample with acetonitrile, salting-out with magnesium sulfate (MgSO4) and sodium chloride, and cleanup of the resulting extracts with dispersive solid-phase extraction using primary-secondary amine, graphitized carbon black, and MgSO4. Fortification studies were performed for 102 organophosphorus pesticides at 1.0, 10, and 100 ppb in 4 different pesticide-free commodities (grape, orange, spinach, and tomato). Recoveries ranged from 63-125%, with >80% being achieved for most of the pesticides tested in each commodity. The procedure was applied to the analysis of 400 produce samples collected from a cohort of children that participated in the Children's Pesticide Exposure Study and the Longitudinal Dietary Pesticide Exposure Study in which selected 24 h duplicate food items were collected throughout a 12-month period. Residues of 15 of the 102 pesticides were detected at levels ranging from <1 to 526 ppb.
authors.affiliation: U.S. Food and Drug Administration, Office of Regulatory Affairs, 60 Eighth St NE, Atlanta, GA 30309, USA. fschenck@live.com
authors.forename: Frank
authors.initials: F
authors.lastname: Schenck
authors.forename: Jon
authors.initials: J
authors.lastname: Wong
authors.forename: Chenseng
authors.initials: C
authors.lastname: Lu
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Jim R
authors.initials: JR
authors.lastname: Holcomb
authors.forename: LaTonya M
authors.initials: LM
authors.lastname: Mitchell
mesh_terms: D005410:Flame Ionization / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods*; D014675:Vegetables / Q000737:chemistry
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides