Determination of multiresidue quinolones regulated by the European Union in pig liver samples : High-resolution time-of-flight mass spectrometry versus tandem mass spectrometry detection

The use of liquid chromatography coupled to orthogonal acceleration time-of-flight mass spectrometry (LC–ToF-MS) provides an attractive alternative to liquid chromatography coupled to quadrupole (LC–MS) or triple quadrupole mass spectrometry (LC–MS/MS) in multiresidue analysis. ToF-MS provides accurate mass information and a significantly higher mass resolution than quadrupole analyzers. In this work, the influential parameters in time-of-flight detection using an electrospray ionization (ESI) source were studied using a central composite design to obtain the main effects and their two-factor interactions. The method developed uses LC–ESI-ToF-MS to determine and characterize quinolones regulated by the EU in pig liver samples below the maximum residue limits (MRLs). Linearity, decision limit, detection capability, detection and quantification limits, precision and recoveries were determined and adequate results were obtained, with quantification limits between 1.5 and 6 μg kg−1 and recoveries higher than 60% for all quinolones. Limits of detection are lower than 2 μg kg−1. Results obtained using LC–ESI-ToF-MS were compared with those obtained using LC coupled to a quadrupole and to triple quadrupole mass spectrometer. The work described in this paper illustrates the suitability and excellent confirmatory potential of LC–ToF-MS for multiresidue analysis in food samples.