Matrix Effects in the Residue Detection of β_2-agonists in Pig Urine by UPLC-MS/MS

To investigate the matrix effects in the residue detection of β2-agonists in pig urine and eliminating methods,pig urine samples were acidolysised by perchloric acid,extracted with ethyl acetate and methyl tertiary butyl ether,the extracts were applied to MCX cartridge for cleanup,the separation was performed by ultra performance liquid chromatography-tandem mass spectrometry.71.0%-114.5% levels of matrix effects were found in 8 β2-agonists detection.The internal standard method and matrix dilution calibration curve were compared to eliminate matrix effect.The results showed that,quantitative results of the internal standard method was 64.7%-136.0%,matrix spiked calibration curve quantitative results was 77.9%-117.9%,with 5.0mL pig urine at 0.4ng/mL,1.0ng/mL and 2.0ng/mL standard added.The quantitative matrix spiked calibration curve was more stable,and internal standard method could be replaced by matrix spiked calibration curve for quantitative.