Abstract: A rapid method was presented for the determination of 9 macrolide antibiotics in pork samples by ultra-high performance liquid chromatography-quadrupole/orbitrap high resolution mass spectrometry. The samples were extracted with acetonitrile and the extract was defatted with n-hexane and then separated with a Waters Acquity BEH C18 column (2.1 mm × 100 mm, 1.7 μm) by gradient elution using a binary solvent system composed of methanol and 0.1% formic acid in water. The analytes were detected by quadrupole-orbitrap high resolution mass spectrometry in the full-scan and data-dependent scan (ddMS2) mode. The results showed that the deviation between the theoretical and measured accurate mass-to-charge ratio was lower than 1.0 × 10-6, and good linear relationships were observed in the concentration range of 0.5–100 ng/mL for the 9 antibiotics with correlation coefficients higher than 0.998. The limits of detection were in the range of 0.05–0.2 μg/kg and the limits of quantification were in the range of 0.1–0.4 μg/kg. The recoveries of the method ranged from 69.4% to 107.6% at spiked concentration levels of 0.1–4.0 μg/kg, with relative standard deviations (RSDs) lower than 10%. This method proved to be simple, rapid, and accurate, and therefore it was suitable for rapid screening for and quantitative analysis of 9 macrolides antibiotics in pork samples.

Key words: ultra-high performance liquid chromatography, quadrupole/orbitrap high resolution mass spectrometry, pork samples, macrolide antibiotics, determination