Transfer assessment of fipronil residues from feed to cow milk

• Published in: Talanta (Oxford) 2007-10, Vol.73 (4), p.710-717
• Main Authors: Le Faouder, J., Bichon, E., Brunschwig, P., Landelle, R., Andre, F., Le Bizec, B.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Apis mellifera; Applied sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Cow milk; Exact sciences and technology; Fipronil; Gas chromatographic methods; GC–MS/MS; Global environmental pollution; Pollution; Spectrometric and optical methods; Transfer; Triticum aestivum; Zea mays
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2007.04.061

Fipronil, a phenylpyrazole insecticide introduced for pest control on a broad range of crops, can also affect non-target insects such as honeybees. More widely, non-target environment such as milk produced by dairy cows fed with maize silage from treated seeds (=silage T) can be affected. To assess the potential transfer of fipronil residues (sulfone, sulfide, fipronil, desulfinyl and amide), a methodology including gas chromatography coupled with tandem mass spectrometry (GC–MS/MS) analysis was developed and validated according to the 2002/657/EC decision, in order to reach a level of quantification below 0.1 μg L −1 in milk and 0.1 μg kg −1 in plants. Twelve dairy cows were fed with silage T during 4 months. Concentration of fipronil in treated seeds was estimated at 1 g kg −1, whereas silage from these seeds contained 0.30 ± 0.05 μg kg −1 of dry material of fipronil, 0.13 ± 0.03 μg kg −1 of dry material of sulfone. Sulfide residues were below the limit of quantification. Silage from untreated seeds (=silage U) presented traces of fipronil and sulfone, respectively at 0.04 ± 0.06 and 0.02 ± 0.03 μg kg −1 of dry material. Contribution of fipronil residues from supplies was insignificant. During administration of silage T, only sulfone residues were quantified in milk. The average concentration was 0.14 ± 0.05 μg L −1. Before and after administration, sulfone residues were detected but not quantifiable (