Determination of Residual Chloramphenicol in Chicken Meat by Liquid Chromatography-Tandem Mass Spectrometry

A sensitive liquid chromatography—tandem mass spectrometric method has been optimized for determination of residual chloramphenicol (CAP) in chicken meat. Chicken meat samples were extracted with ethyl acetate, aliquot was evaporated to dryness and reconstituted in mobile phase. LC separation was carried out on a BEH C₁₈ column (100mm×2.1 mm, 1.7µm) column with gradient elution mode using mobile phase consisting of acetonitrile and 0.01mM ammonium acetate. LC-MS/MS analysis was done in multiple reaction monitoring (MRM) mode through an ESI interface operated in negative ionisation mode, with deuterated chloramphenicol-d5 as internal standard. Four identification points were obtained for CAP with one precursor ion and two product ions. Identification and quantification of the CAP were performed based upon the intensities of mass fragments from the precursor ions, MRM of CAP:320.84>151.52, 320.84>256.84; MRM of d5-CAP - 325.84>156.54, respectively. Linear matrix-matched calibration curves were obtained (regression coefficient ≥ 0.99) over the quantitation range of 0.05-2 µg/Kg with the limit of quantitation (LOQ) being 0.05 µg/Kg. Mean recoveries ranged from 97% to 103%, with the corresponding intra-day variation ranging from 1.10% to 3.46%, based on the spike concentration around MRPL. The proposed tandem mass spectrometric method is quite adequate for routine monitoring of residual chloramphenicol in chicken meat at and below EU MRPL (0.15µg/Kg).