Determination of chloramphenicol residues in meat, seafood, egg, honey, milk, plasma and urine with liquid chromatography–tandem mass spectrometry, and the validation of the method based on 2002/657/EC

A simple and rapid method for the determination and confirmation of chloramphenicol in several food matrices with LC–MS/MS was developed. Following addition of d5-chloramphenicol as internal standard, meat, seafood, egg, honey and milk samples were extracted with acetonitrile. Chloroform was then added to remove water. After evaporation, the residues were reconstituted in methanol/water (3 + 4) before injection. The urine and plasma samples were after addition of internal standard applied to a Chem Elut extraction cartridge, eluted with ethyl acetate, and hexane washed. Also these samples were reconstituted in methanol/water (3 + 4) after evaporation. By using an MRM acquisition method in negative ionization mode, the transitions 321 → 152, 321 → 194 and 326 → 157 were used for quantification, confirmation and internal standard, respectively. Quantification of chloramphenicol positive samples regardless of matrix could be achieved with a common water based calibration curve. The validation of the method was based on EU-decision 2002/657 and different ways of calculating CCα and CCβ were evaluated. The common CCα and CCβ for all matrices were 0.02 and 0.04 μg/kg for the 321 → 152 ion transition, and 0.02 and 0.03 μg/kg for the 321 → 194 ion transition. At fortification level 0.1 μg/kg the within-laboratory reproducibility is below 25%.