title: Development of an Immunoassay for the Detection of the Phenylpyrazole Insecticide Fipronil.
abstract: Phenylpyrazole insecticides such as fipronil have been used as replacements for organophosphates. The wide application of fipronil raises concern about environmental contamination and risk for fish, birds, and other nontargeted beings as well as human health. A sensitive, competitive indirect heterologous enzyme-linked immunosorbent assay (ELISA) was developed. Antibodies with different specificities to fipronil and its metabolites were produced. Two ELISAs having IC50 values of 0.58 ± 0.06 and 2.6 ± 0.4 ng/mL were developed. Design of different haptens and coating antigens resulted in two assays with distinct cross-reactivity patterns for structurally related compounds: 96, 38, and 101% versus 39, 1.4, and 25% for fipronil-sulfide, fipronil-detrifluoromethylsulfonyl, and fipronil-desulfinyl, respectively. Performance of the immunoassays was demonstrated by a recovery study from spiked water and human serum and urine matrices, giving recovery values in the range of 85-111% for different concentrations. The assays demonstrated good correlation in fipronil recovery with conventional LC-MS/MS analysis. The generic assay 2265 has the sensitivity to measure fipronil and its analogs in serum at levels relevant for exposure monitoring. The assays were used to analyze human urine samples obtained from exposure studies and serum samples from rats treated with a fipronil-containing diet.
authors.affiliation: †Department of Entomology and Nematology and ‡UCD Comprehensive Cancer Center, University of California, Davis, California 95616, United States.
authors.forename: Natalia
authors.initials: N
authors.lastname: Vasylieva
authors.affiliation: †Department of Entomology and Nematology and ‡UCD Comprehensive Cancer Center, University of California, Davis, California 95616, United States.
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Ahn
authors.affiliation: †Department of Entomology and Nematology and ‡UCD Comprehensive Cancer Center, University of California, Davis, California 95616, United States.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Barnych
authors.affiliation: †Department of Entomology and Nematology and ‡UCD Comprehensive Cancer Center, University of California, Davis, California 95616, United States.
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Gee
authors.affiliation: †Department of Entomology and Nematology and ‡UCD Comprehensive Cancer Center, University of California, Davis, California 95616, United States.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D000941:Antigens / Q000378:metabolism; D002853:Chromatography, Liquid; D003429:Cross Reactions / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006241:Haptens / Q000737:chemistry / Q000276:immunology; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007118:Immunoassay / Q000379:methods*; D007306:Insecticides / Q000032:analysis* / Q000737:chemistry; D008297:Male; D011720:Pyrazoles / Q000032:analysis* / Q000097:blood / Q000737:chemistry / Q000652:urine; D051381:Rats; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry; D014867:Water / Q000737:chemistry
chemical_list: D000906:Antibodies; D000941:Antigens; D006241:Haptens; D007106:Immune Sera; D007306:Insecticides; D011720:Pyrazoles; D014867:Water; C082360:fipronil