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A fast liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is developed to determine lincomycin (LM) in honey, muscle, milk, and egg. Samples are cleaned-up at pH 4.7 using Strata-X-C mixed-mode polymeric strong cation exchange solid-phase extraction (SPE) cartridges, which could selectively adsorb the lincomycin from matrices under the acidic condition. LM is separated on the recently introduced Kinetex XB core-shell type HPLC column using isocratic elution mode with a mobile phase containing 0.1% formic acid in water/acetonitrile (93/7, v/v, pH 2.6) at a flow rate of 0.7 mL/min. The subsequent MS/MS detection has decreased ion effect, which allows the limit of detection (LOD) of LM for honey to be 0.05 µg/kg for honey and 0.5 µg/kg for muscle, milk, and egg. These LODs are much lower than those reported previously. The other main advantage of the developed method is the analysis time of only 3.5 min, which is about three times shorter than other reported LC-MS-MS methods. Recoveries varies between 94.2% and 125.2% and in-house reproducibility ranges from 3.7% to 28.7%. The developed method is validated according to European Union (EU) Commission Decision 2002/657/EC using a matrix-comprehensive validation strategy. All studied analytical parameters fulfills the EU guidelines.

A new liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed to confirm chloramphenicol (CAP) residues in foods of animal origin and in urine samples, which were earlier found positive under the screening analysis, performed by competitive enzyme-linked immunoassay (ELISA) technique. The developed LC-MS/MS method was applied to four non-compliant samples from 2008 to 2012; giving concentrations of CAP residues from 1.18 to 3.68 µg kg -1 . All samples, qualified positive by ELISA, were confirmed with the LC-MS/MS technique and found to be non-compliant. The effectiveness of the confirmatory method was proven by participating in a successful proficiency test in year 2010. Both LC-MS/MS and ELISA methods were validated according to the European Union 2002/657/EC decision. The decision limit of the confirmatory method was determined as 0.02 µg kg -1 for CAP in each validated matrix, while the detection capability of the screening test was 0.15 µg kg -1 .