title: Determination of acephate in human urine.
abstract: Acephate is a commonly used organophosphate insecticide applied on agricultural crops and in residential communities. Because very little acephate is metabolized prior to excretion, the parent pesticide compound can be measured in human urine. The residue method must be sensitive enough to determine human exposure and potential health risk for both agricultural workers and their families who may be exposed by pesticide drift or by inadvertent carry-home residues. A reliable and sensitive method was developed to measure acephate concentrations in human urine. Urine was diluted with water and acetone, adjusted to a neutral pH, and partitioned twice in acetone-methylene chloride (1 + 1, v/v), with NaCl added to aid separation. The solvent-reduced organic phase extracts were clarified by activated charcoal solid-phase extraction and then adjusted to a final volume with the addition of a D-xylose analyte protectant solution to reduce matrix enhancement effects. Acephate concentrations in urine were determined by gas chromatography using pulsed flame photometric detection. The method limit of detection was established at 2 microg/L, with a method limit of quantitation of 10 microg/L. The average recovery from urine fortified with 10-500 microg/L was 102 +/- 12% (n = 32).
authors.affiliation: Washington State University, Food and Environmental Quality Laboratory, 2710 University Dr, Richland, WA 99354, USA.
authors.forename: Jane T
authors.initials: JT
authors.lastname: LePage
authors.forename: Vincent R
authors.initials: VR
authors.lastname: Hebert
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Tomaszewska
authors.forename: Joan E
authors.initials: JE
authors.lastname: Rothlein
authors.forename: Linda
authors.initials: L
authors.lastname: McCauley
mesh_terms: D000096:Acetone / Q000032:analysis; D002625:Chemistry, Organic / Q000379:methods; D002849:Chromatography, Gas; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000032:analysis* / Q000737:chemistry / Q000652:urine*; D008752:Methylene Chloride / Q000032:analysis; D008956:Models, Chemical; D009943:Organophosphorus Compounds / Q000032:analysis; D009946:Organothiophosphorus Compounds / Q000032:analysis* / Q000737:chemistry / Q000652:urine*; D010573:Pesticide Residues / Q000032:analysis; D063088:Phosphoramides; D012015:Reference Standards; D015203:Reproducibility of Results; D012306:Risk; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D012997:Solvents; D016482:Urinalysis / Q000379:methods*; D014556:Urine; D014994:Xylose / Q000737:chemistry
chemical_list: D007306:Insecticides; D009943:Organophosphorus Compounds; D009946:Organothiophosphorus Compounds; D010573:Pesticide Residues; D063088:Phosphoramides; D012997:Solvents; D000096:Acetone; C001969:acephate; D012965:Sodium Chloride; D008752:Methylene Chloride; D014994:Xylose