A New Single-Laboratory Validated Method for the Detection of Pyrethroid Metabolites in Milk by GC/MS

With concerns over the household use of pyrethroid pesticides for mosquito control, researchers in Thailand have developed a validated method for analyzing cis/trans-permethrinic acid in powdered milk.

Pyrethroids are naturally occurring pesticides that are synthesized to manufacture mosquito coils and sprays for home use.  These pesticides can bioaccumulate in women’s bodies and be excreted in breast milk as metabolites or the original product.  This study substitutes powdered milk as an analog for human breast milk.

Milk was prepared from formula per the manufacturer’s instructions and used as a matrix for the calibrants (in acetone) at concentrations ranging from 0.05 – 10.00 µg/mL. β-naphthol, dissolved in toluene, was used as an internal standard at 0.01 µg/mL.  50 µL of all standards, QC, and samples were added to 1.5 mL centrifuge tubes and evaporated to dryness at 40ºC.  20 µL of derivatizing reagent MTBSTFA ((N-(tert-Butyldimethylsilyl)-N-methyltrifluoroacetamide, 98%) from UCT, Inc. (MTBSTFA-0-100) and 50 µL of IS were added to each of the dried tubes and sonicated for 10 minutes.  The samples were then incubated at 80 ºC for 10 minutes before being injected into the GC/MS.


For more information please visit the original paper.

Sonti, P., Tummarintra, P., Keawbundit, P., Wongman, A. ., & Duongkaew, M. . (2022). Rapid, Reliable and Accurate Method for Detecting of Pyrethroid Metabolite Contaminant in Synthetic Milk Using Gas Chromatography-Mass Spectrometry. Thai Journal of Toxicology, 37(1), 16–26. Retrieved from https://li01.tci-thaijo.org/index.php/ThaiJToxicol/article/view/246993

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