Determination of Pesticide Residues in Ectoparasiticide-Impregnated Collars Using Ultrasound-Assisted Extraction and Liquid Chromatography–Mass Spectrometry

Ectoparasiticide-impregnated collars are used on dogs and cats to control zoonoses, acting as repellents and/or killing vectors. The contact of animals or people with pesticides can cause intoxication, so ectoparasiticide-impregnated collars may be a potentially important source of these compounds. The aim of this work was to develop a method for the determination of propoxur, dichlorvos, diazinon, chlorpyrifos, deltamethrin, and flumethrin in commercial ectoparasiticide-impregnated collars, using ultrasound-assisted extraction and liquid chromatography–mass spectrometry. The total ultrasound extraction time was 45 min, resulting in recovery values between 40 ± 6% and 103 ± 8%, in the concentration range from 0.005 to 1.0 mg L⁻¹. Under optimal conditions, good linearity and sensitivity were obtained in the concentration range from 0.005 to 5.0 mg L⁻¹ with coefficients of determination above 0.99. The relative standard deviations for triplicate determinations were lower than 24%, and the limits of detection and quantification were in the ranges 0.013–1.36 and 0.036–4.13 mg kg⁻¹, respectively. The proposed method was applied in the analysis of a commercial collar, after its expiry date, and flumethrin residues were found.