In-line solid-phase extraction preconcentration in capillary electrophoresis-tandem mass spectrometry for the multiresidue detection of quinolones in meat by pressurized liquid extraction

Abstract

We have developed and validated a CE-MS/MS method using an in-line SPE device (analyte concentrator, AC) to determine eight quinolones of veterinary use whose maximum residue levels in animal edible tissues are established by the EU Council Regulation 2377/90, i.e., danofloxacin, sarafloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine. Different parameters affecting the AC performance, such as its design (in this case frit-free), the kind of sorbent (Oasis® MCX), sample pH, volume, and composition of the elution plug and injection time were studied. The method was validated using standard solutions obtaining LODs between 17 and 59 ng/L. Finally, a pressurized liquid extraction (PLE) method was developed to determine these antibiotics in chicken muscle samples. The whole analytical method was validated in terms of linearity (r2 ≥ 0.992), recoveries (63-112%), repeatability and intermediate precision (RSD ≤ 20%), LODs (40-140 ng/kg) and LOQs (130-470 ng/kg), showing the usefulness of the combination of in-line SPE-CE-MS/MS with PLE for the identification and simultaneous quantification of eight regulated quinolone antibiotics in chicken muscle at very low concentration levels. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.