Determination of Fipronil and Its Metabolites in Eggs and Environmental Matrices by LC-MS/MS

Fipronil is a widely used insecticide. Exposure of humans to fipronil can cause harmful health effects. The aim of the present work is to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid detection of fipronil and its metabolites in eggs and environmental matrices (soil, feed, and chicken feed bags). Solvent extraction was performed with a mixture including water, acetonitrile, and sodium chloride, followed by purification using a solid-phase extraction column. The LC separation was accomplished on a C18 column, and the detection was performed with a triple quadrupole mass spectrometer using electrospray ionization in multiple reaction monitoring (MRM) mode. The results showed a good linear relationship between fipronil and its metabolites in the range of 0.01 to 20 ng/mL, and the linear correlation coefficients ([R.sup.2]) were all greater than 0.999. The detection and quantification limits of the method for all analytes were 0.01 and 0.05 ng/mL, respectively. The precision expressed as coefficients of variation (n = 3) for assay of fipronil and its metabolites ranged from 8.4% to 13.2% at three levels (0.1 ng/mL, 1 ng/mL, and 10 ng/mL). The recoveries ranged from 81.3% to ~119.5%. Finally, we successfully employed the method to a case of fipronil contamination, and found residues of fipronil and its metabolites in eggs and the environmental matrix.
Fipronil is a type of benzopyrazole insecticide developed in 1987 by Bayer Scientific Crops Co. Ltd. (1), and is widely used to control crop pests in vegetables, rice, tobacco, cotton, [...]