LC determination of chloramphenicol in honey using dispersive liquid-liquid microextraction

A novel method, dispersive liquid-liquid microextraction coupled with liquid chromatography-variable wavelength detector (LC-VWD), has been developed for the determination of chloramphenicol (CAP) in honey. A mixture of extraction solvent (30 mu L 1,1,2,2-tetrachloroethane) and dispersive solvent (1.00 mL acetonitrile) were rapidly injected by syringe into a 5.0 mL real sample for the formation of cloudy solution, the analyte in the sample was extracted into the fine droplets of C2H2Cl4. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was determined by LC-VWD. Some important parameters, such as the kind and volume of extraction solvent and dispersive solvent, extraction time, sample solution pH, sample volume and salt effect were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 3 to 2,000 mu g kg(-1) for target analyte. The enrichment factor for CAP was 68.2, and the limit of detection (S/N = 3) were 0.6 mu g kg(-1). The relative standard deviation (RSD) for the extraction of 10 mu g kg(-1) of CAP was 4.3% (n = 6). The main advantages of method are high speed, high enrichment factor, high recovery, good repeatability and extraction solvent volume at mu L level. Honey samples were successfully analyzed using the proposed method.