Simultaneous analysis of antibiotic residues in food matrices using hydeophilic interaction coupled with tandem mass spectrometry

Abstract

In this study, simple and sensitive method for simultaneous analysis of twenty four antibiotics belong to eight important classes : four sulfonamides, four quinolones, four macrolides, three tetracyclines, three aminoglycosides, three penicillins, two lincosamides, and amprolium in food was developed. The method involved a liquid extraction with the mixture of acetonitrile and 2% trichloroacetic acid in equal ratio, and removed fat with hexane before dilution of an extract with 10% formic acid : acetonitrile (9:1), and followed by hydrophilic interaction liquid chromatography (HILIC)-electrospray ionization tandem mass spectrometry in positive ion mode. The combination of effective extraction procedure and HILIC separation technique allowed quantification and confirmation of compounds with different polarity in a single chromatographic analysis. Several parameters affecting on the extraction efficiency, separation and sensitivity were optimized. The validation method has been performed in chicken matrix according to European Union Decision 2002/657/EC. Good performance data were obtained for recovery, precision, calibration curve, specificity and limit of detection. The average recoveries for all targeted analytes at MRLs concentration level were obtained in the range of 57 to 99 % with satisfactory %RSD of 2-14 (n=10) and also lower than acceptable value calculated from Horwitz equation. The limits of detection were 0.1-20 µg/kg for all compounds. Good linearity covered the concentration range of 0.25 MRL-2 MRL (sulfonamides ranged from 0.05 MRL-MRL, enrofloxacin and ciprofloxacin ranged from 0.1 MRL-MRL) with coefficient of determination higher than 0.99. The optimized method has been successfully applied to real chicken samples which can be detected enrofloxacin at 6.5 µg/kg. The method can also be employed for shrimp and egg samples analysis in routine laboratory for a different class of antibiotic residues from various matrices