Determination and confirmation of chloramphenicol in honey, fish and prawns by liquid chromatography-tandem mass spectrometry with minimum sample preparation: validation according to 2002/657/EC Directive

A reliable, simple and sensitive liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) confirmation method has been developed for chloramphenicol (CAP) determination in honey, fish and prawns. For honey, samples were extracted with ethyl acetate, an aliquot was evaporated to dryness and re-dissolved in mobile phase. For fish and prawns, tissues were extracted with acetonitrile and chloroform. The organic layer was evaporated to dryness and the residue was re-constituted with water: acetonitrile (90: 10). LC separation was achieved on a C18 column with gradient elution using a mobile phase of acetonitrile and water. Analysis was carried out on a triple-quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode via electrospray interface operated in negative ionisation mode, with deuterated chloramphenicol-d(5) (d(5)-CAP) as internal standard. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Four identification points were obtained for CAP with one precursor ion and two product ions. The limit of detection (LOD) was 0.02 mu g kg(-1). Linear calibration curves were obtained over concentration ranges of 0.1-1.0 mu g kg(-1) in tissues. Mean recoveries ranged from 85.5% to 115.6%, with the corresponding intra-and inter-day variation ranging from 1.0% to 22.5%, depending on matrix type and level of concentration. The decision limit (CC alpha) and detection capability (CC beta) of the method were obtained for all matrices: 0.04 and 0.06 mu g kg(-1), respectively, for prawns and fish and 0.05 and 0.09 mu g kg(-1) for honey.