[Simultaneous determination of seven avermectin residues in aquatic products by modified QuEChERS combined with high-performance liquid chromatography-tandem mass spectrometry].

A method was established for the simultaneous determination of seven avermectin (AVMs) residues, such as avermectin, ivermectin, doramectin, selamectin, eprinomectin, moxidectin and emamectin, in aquatic products using modified QuEChERS and high-performance liquid chromatography -tandem mass spectrometry (HPLC-MS/MS). The samples were extracted with 0.2% (v/v) ammoniate acetonitrile, and then 3 g of anhydrous magnesium sulfate and 2 g of anhydrous sodium sulfate were added to remove moisture and precipitate proteins. The samples were purified with 100 mg of C and 500 mg of anhydrous magnesium sulfate. The mobile phases comprised of acetonitrile (containing 0.1% (v/v) formic acid and 5 mmol/L ammonium acetate) and water (containing 0.1% (v/v) formic acid and 5 mmol/L ammonium acetate). The prepared samples were separated on a Varian Pursuit ULTRA C column (100 mm×2.0 mm, 2.8 μm) and determined using heated electrospray ionization (HESI) in the positive ion multiple reaction monitoring (MRM) mode. The analytes were quantified using external standard with the matrix-matched standard calibration curve method. The results showed that the solvent and matrix-matched standard curves for avermectin, ivermectin, doramectin, selamectin, eprinomectin and moxidectin in the range of 2-200 μg/L and for emamectin in the range of 0.2-20 μg/L were all linear, and the correlation coefficients () were ≥ 0.9972. The recoveries were 71.6%-112.8% with the relative standard deviations in the range of 4.7%-13.1%. The limits of quantification (LOQs) for avermectin, ivermectin, doramectin, selamectin, eprinomectin and moxidectin were all 5 μg/kg and for emamectin was 0.25 μg/kg. The present method is simple, repeatable, and suitable for the simultaneous determination of the residues of the seven avermectins in aquatic products.