Search

Abstract A reliable ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous identification and quantification of 22 β-agonist residues in swine muscle and liver tissues. A special focus was given to sample the pretreatment procedures and was crucial for an accurate and reliable analytical method. With regard to the high complexity of food matrices, the extraction solvent, time, and temperature, as well as clean-up cartridges, were optimized to improve the extraction efficiency and reduce matrix effects. The UHPLC-MS/MS method was further validated by determining the linearity (R2 ≥ 0.9900), sensitivity (limit of detection varying from 0.05 μg/kg to 0.8 μg/kg, limit of quantitation ranging from 0.2 μg/kg to 2.5 μg/kg), recovery (ranging from 76.4 to 111.7%) and precision (≤22.9%) in swine muscle and liver tissues. The UHPLC-MS/MS method was proven to be suitable for both screening and the confirmatory determination of 22 β-agonist residues in swine muscle and liver tissues. [ABSTRACT FROM AUTHOR]

A multi-class multi-residue analysis method for determination of veterinary drugs, pesticides and mycotoxins in dairy products by liquid chromatography–tandem mass spectrometry (LC–MS/MS) has been established. These 17 classes, a total of 40 kinds of target compounds were chosen because their administration to food-producing animals is banned or regulated in China and may be potentially abused or misused. Samples were extracted with acetonitrile–ethyl acetate–acetic acid (49.5 + 49.5 + 1, v/v/v). Most of lipids in the extract were removed by low-temperature cleanup, prior to solid phase extraction on HLB cartridges. The quantification and confirmation of the 40 analytes were performed by LC–MS/MS with electro-spray ionization (ESI) interface in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) and limits of quantification (LOQs) were 0.006–0.3 μg/kg and 0.02–1.0 μg/kg, respectively. The spiked recoveries in milk, yogurt, milk powder and cheese samples were from 67.3% to 106.9%. The repeatability and the within-laboratory reproducibility were less than 12.7% and 13.9%. Applying this method, our results revealed the presences of chloramphenicol, cimeterol, and flunixin at the concentration of 0.027–0.452 μg/kg in some samples. [ABSTRACT FROM AUTHOR]