RESUMO
Objective To establish a reliable pretreatment method for the detection of mequindox and its metabolite in pork luncheon meat by ultra-performance liquid chromatography/triple qudrupole tandem mass spectrometry. Methods Samples were extracted with ethyl acetate, and the results of purification and enrichment by PAX and PEP solid-phase extraction columns were analyzed. Acetonitrile/methanol (3:11) - 0.1% formic acid water was used as the mobile phase, and Shimadzu Inertsil ODS-3-column (3µm, 2.1 × 100mm) chromatographic columns were used for qualitative and quantitative analysis using the multi-reaction detection positive ion mode. Results The results showed that PEP cartridge had good recovery rate. The detection limit of mequindox was 0.10µg/kg, and limit of quantitation was 0.30µg/kg. The average recoveries for spiked levels of 0.33, 0.83, and 1.65µg/kg were 127%, 72.0%, and 60.1%, respectively. The detection limit of 2-quinoxalinecarboxylic acid was 0.10µg/kg, and limit of quantitation was 0.40µg/kg. The average recoveries for spiked levels of 0.42, 1.05, and 2.1µg/kg were 125%, 99.0%, and 60.9%, respectively. Conclusion This method is suitable for the determination of mequindox and its metabolite 2-quinoxalinecarboxylic acid in luncheon meat.