Abstract:

A method has been developed for the simultaneous determination of the 10 kinds of 121 veterinary drugs (including chloramphenicols, β -agonists, sulfonamides, 4-quinolones, nitroimidazoles, macrolides, avermections, polyether antibiotics, tetracycline antibiotics, cephalosporins, etc.) in pork using QuEChERS method coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The drugs were extracted with Na₂EDTA-McIlvaine buffer solution (pH=4) and acetonitrile. Anhydrous sodium sulfate was used for the salting-out process. The solutions divided into two groups were cleaned-up by different mixed sorbents. The drugs were analyzed by UPLC-MS/MS in multiple reaction monitoring (MRM) mode via electrospray ionization. Among the 121 drugs, 5 drugs were quantified by internal standard method, and the other 116 drugs were quantified by external standard method. The calibration curves of the 121 drugs were linear in the range of 0.02-40 μg/L with the correlation coefficients more than 0.99. The limits of quantification (LOQs, S/N=10) were 0.05-10 μg/kg. The average recoveries of 8 drugs at LOQ level in pork ranged from 41.7% to 59.6% with the relative standard deviations (RSDs) of 1.7%-13.5%. The average recoveries of 10 drugs at LOQ level in pork ranged from 122.6% to 163.2% with the RSDs of 0.6%-14.8%. The average recoveries of 103 drugs at LOQ level in pork ranged from 60.3% to 118.3% with the RSDs of 0.4%-16.7%. The proposed method is rapid, simple, sensitive, reliable and cost-effective.

Key words: grouping purification, pork, QuEChERS, ultra performance liquid chromatography-tandem mass (UPLC-MS), veterinary drugs