Hydroxy-fipronil is a new urinary biomarker of exposure to fipronil.
Occupational medical surveillance is highly desirable in manufacturing facilities where exposure to chemicals is significant. The insecticide fipronil is generally considered safe for humans but with increasing use, exposure to fipronil is of concern. Identification of urinary metabolites of fipronil may allow development of affordable, cheap and rapid procedures for human exposure evaluation. In this study we developed a fast and easy approach for synthesis of hydroxy-fipronil, a potential urinary metabolite of fipronil. This standard was used to develop a sensitive analytical LC-MS/MS method with a limit of quantification (LOQ) of 0.4ng/mL. Fipronil sulfone, a known metabolite, and hydroxy-fipronil were quantified in urine samples from rats treated with a fipronil containing diet. Fipronil sulfone concentration centered around 20ng/mL, while the concentration of hydroxy-fipronil was dose-dependent ranging in 10-10,000ng/mL and thus being a more sensitive marker of fipronil exposure. A fipronil immunoassay with cross-reactivity to hydroxy-fipronil showed a good correlation in signal intensity with LC-MS data. It was also used to demonstrate the applicability of the method for sample screening in the evaluation of exposure levels.
Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, United States.
Natalia
N
Vasylieva
Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, United States.
Bogdan
B
Barnych
Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, United States.
Debin
D
Wan
Faculty of Agriculture, Plant Protection Department, Zagazig University, Egypt.
El-Sayed A
EA
El-Sheikh
Department of Pharmacology, University of California Davis, Davis, CA 95616, United States.
Hai M
HM
Nguyen
Department of Pharmacology, University of California Davis, Davis, CA 95616, United States.
Heike
H
Wulff
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC, United States.
Rebecca
R
McMahen
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC, United States.
Mark
M
Strynar
Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, United States.
Shirley J
SJ
Gee
Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California Davis, Davis, CA 95616, United States. Electronic address: bdhammock@ucdavis.edu.
Bruce D
BD
Hammock
D000818:Animals; D002853:Chromatography, Liquid; D007306:Insecticides / Q000493:pharmacokinetics / Q000592:standards / Q000652:urine*; D057230:Limit of Detection; D011720:Pyrazoles / Q000493:pharmacokinetics / Q000592:standards / Q000652:urine*; D051381:Rats; D053719:Tandem Mass Spectrometry
D007306:Insecticides; D011720:Pyrazoles; C534368:fipronil sulfone; C082360:fipronil
Antibody; GABA receptor bioassay; Immunoassay; Insecticide; LC-MS/MS; Metabolite; Screening; Sensor