Determination of chloramphenicol in propolis in China markets by liquid chromatography/tandem mass spectrometry

A method based on high performance liquid chromatography tandem mass spectrometry was established for the determination of chloramphenicol (CAP) residues in propolis. The propolis samples were dissolved with 1 M sodium hydroxide (NaOH), acidified with 5% perchloric acid ( HCIO₄ ), then were adjusted to pH=10 with 1M NaOH. The solutions were extracted with ethyl acetate, followed by treatment with n-hexane for defatting. D5- chloramphenicol (CAP-D5) was utilized as internal standard. The results showed that linearity of the method was good with correlation coefficients (R²) of 0.9999 in the range of 0.2 to 10μg/kg. The detection limit was 0.05μg/kg. The recoveries varied from 89.0% to 94.3% with the relative standard deviation (RSD) from 5.78% to 10.25%. Using this method, the concentrations of CAP in 8 propolis samples collected in China markets were determined with content ranged from <;0.05 to 0.95μg/kg. The method is sensitive, reproducible and suitable for the determination of CAP residues in propolis.