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Use of phenyl/tetrazolyl-functionalized magnetic microspheres and stable isotope labeled internal standards for significant reduction of matrix effect in determination of nine fluoroquinolones by liquid chromatography-quadrupole linear ion trap mass spectrometry
- Xu, Fei, Liu, Feng, Wang, Chaozhan, Wei, Yinmao
- Analytical and bioanalytical chemistry 2018 v.410 no.6 pp. 1709-1724
- adsorbents, fluoroquinolones, food safety, hydrophobicity, ions, liquid chromatography, magnetism, mass spectrometry, microparticles, moieties, monitoring, pork, risk, solid phase extraction, stable isotopes, China
- In this study, the strategy of unique adsorbent combined with isotope labeled internal standards was used to significantly reduce the matrix effect for the enrichment and analysis of nine fluoroquinolones in a complex sample by liquid chromatography coupled to quadrupole linear ion trap mass spectrometry (LC-QqQLIT-MS/MS). The adsorbent was prepared conveniently by functionalizing Fe₃O₄@SiO₂ microspheres with phenyl and tetrazolyl groups, which could adsorb fluoroquinolones selectively via hydrophobic, electrostatic, and π–π interactions. The established magnetic solid-phase extraction (MSPE) method as well as using stable isotope labeled internal standards in the next MS/MS detection was able to reduce the matrix effect significantly. In the process of LC-QqQLIT-MS/MS analysis, the precursor and product ions of the analytes were monitored quantitatively and qualitatively on a QTrap system equipped simultaneously with the multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan. Subsequently, the enrichment method combined with LC-QqQLIT-MS/MS demonstrated good analytical features in terms of linearity (7.5–100.0 ng mL⁻¹, r > 0.9960), satisfactory recoveries (88.6%–118.3%) with RSDs < 12.0%, LODs = 0.5 μg kg⁻¹ and LOQs = 1.5 μg kg⁻¹ for all tested analytes. Finally, the developed MSPE-LC-QqQLIT-MS/MS method had been successfully applied to real pork samples for food-safety risk monitoring in Ningxia Province, China. Graphical abstract Mechanism of reducing matrix effect through the as-prepared adsorbent.