LC/MS/MS Analysis of Chloramphenicol in Crab Meat

An LC/MS/MS method is described for the determination and confirmation of chloramphenicol (CAP) in cooked crab meat. It is an extension of another PRLNW-developed LC/MS/MS method (1, 2) for quantitative detection of chloramphenicol in shrimp at the low ppb level. The method involves: pulverization of cooked crab meat with dry ice; extraction of the CAP into ethyl acetate (EtOAc); evaporation (N2) of the EtOAc; addition of methanol, aqueous sodium chloride, and heptane; extraction of the lipids into the heptane, followed by extraction of the aqueous phase with EtOAc; evaporation (N2) of the EtOAc; dissolution into methanol-water; filtration; and separation/detection/confirmation using LC/MS/MS. Crab meat was fortified at 0.10 (1st), 0.10 (2nd), 0.25, 0.50, and 1.0 ng/g (ppb) chloramphenicol. Average absolute recoveries were 53, 51, 67, 84, and 86 % respectively, with RSD’s all less than 1%. Four daughter ions (m/z 152, 176, 194 and 257) were monitored off of the m/z 321 precursor ion. Determination was based on a standard curve using the peak areas of the m/z 15