Determination of avermectins residues in milk by ultra high performance liquid chromatography-tandem mass spectrometry coupled with QuEChERS EMR-Lipid
A QuEChERS EMR-Lipid pretreatment method for determination of avermectins residues in milk was estab-lished by ultra high performance liquid chromatography-tandem mass spectrometry.The avermectins residues in milk were extracted by acetonitrile.After salting-out,the supernatant was cleaned-up by EMR-Lipid.Separation of the analyte was carried out on a PhenomenexKinetex C18 column by gradient elution with 0.1%formic acid and methanol.The avermectins residues were detected by multiple reaction monitoring(MRM)with electrospray ionization(ESI)under positive ion mode.The target compounds were quantified by the matrix-matched external standard method.The mass concentration of four avermectins had a good linear relationship in the range from 0.5 to 20 μg/L with correlation coefficients(r)more than 0.998,and the quantitative limits were 0.071-0.280 μg/kg.The recoveries of avermectins were in the range of 96.6%-108.8%,and the relative standard deviations were 0.98%-4.75%.The method has the merits of simple pretreatment steps and good purification effect.It improved sample detection efficiency.It was suitable for determination of avermectins in a large number of milk samples.
milkavermectinsQuEChERS EMR-Lipidultra high performance liquid chromatography-tandem mass spec-trometry(UPLC-MS/MS)
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