title: Application of an enzyme-linked immunosorbent assay for the analysis of paraquat in human-exposure samples.
abstract: Paraquat is a toxic quaternary ammonium compound used as an herbicide around the world. Easy, fast, and inexpensive but sensitive methods are needed to study the effects of long-term, low-level exposure of paraquat on human health. An enzyme-linked immunosorbent assay (ELISA) was used for quantification of paraquat in urine and air-filter samples collected in a human-exposure study among farm workers in Costa Rica. A sample pretreatment consisted of removal of interfering substances using solid-phase extraction resin columns. The precision and accuracy of the method were tested using duplicate spiked urine samples. The correlation between results for blind samples obtained using ELISA and liquid chromatography-mass spectrometry was significant (R2 = 0.945 and 0.906 for spiked and field samples, respectively). With an LOQ of 2 ng mL(-1), this ELISA method was able to distinguish the exposed from the nonexposed farm workers. For the air-filter analysis, paraquat was extracted by 9 M H2SO4 at 60 degrees C for 12 hours, and the results obtained by ELISA showed good correlation (R2 = 0.918) with the spectrophotometric (256 nm) measurements. Paraquat in acid-stabilized urine samples was very stable, and no significant losses were detected during a 3-month storage at room temperature, at 4 degrees C, or at -20 degrees C.
authors.affiliation: Department of Entomology and the University of California Davis Cancer Center, University of California, Davis, California 95616, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Koivunen
authors.forename: S J
authors.initials: SJ
authors.lastname: Gee
authors.forename: E-K
authors.initials: EK
authors.lastname: Park
authors.forename: K
authors.initials: K
authors.lastname: Lee
authors.forename: M B
authors.initials: MB
authors.lastname: Schenker
authors.forename: B D
authors.initials: BD
authors.lastname: Hammock
mesh_terms: D000393:Air Pollutants; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005374:Filtration; D006540:Herbicides / Q000032:analysis* / Q000652:urine*; D006801:Humans; D016273:Occupational Exposure; D010269:Paraquat / Q000032:analysis* / Q000652:urine*; D011786:Quality Control; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D016482:Urinalysis
chemical_list: D000393:Air Pollutants; D006540:Herbicides; D010269:Paraquat