Analytical Strategy For Regulatory Control Of Chloramphenicol Residues In Aquatic Products

This paper consists of three parts. The first part deals with the screening of CAP by an ELISA method. The second part is concerned about the establishment of a gas chromatographic method for quantitation of CAP. The third part reports the confirmation of CAP by a gas chromatography/mass spectrometric method.Part â…  : For screening purposes commercially available chloramphenicol ELISA kits were used . The results obtained with the screening test indicated that the calibration curve was linear in the range of 0.05-4.05 g/kg with r=0.994. The average recoveries were 84.5% , 88.4% and 81.0% respectively when samples were spiked with 0.45 g/kg, 1.35 g/kg and 4.05 g/kg. The detection limit was 100 g/kg. The within-lab RSD were 6.0%~8.5% and between-labs RSD were 5.8%~14.3%.The method is suitable for the determination of trace chloramphenicol in aquatic products. In screening test false positive results will always occur, all positive samples must be submitted to a confirmatory method.Part â…¡ : For quantitation of CAP a gas chromatographic method has been established. A sample preparation and gas chromatographic parameters were developed, then the method was validated. The calibration curve showed good linearity from 0.5 g/L to 500 g/L with r of 0.999. The detection limit was 0.1 g/kg. The method showed good repeatability. The RSD of injection were 4.4%~6.8%. The RSD for determinations of samples from various preparation were 3.9%~13.5% .When fish, shrimp and crab samples were spiked with 1 g/kg, 4 g/kg and 20 g/kg, the recoveries of fish , shrimp and crab were 86.0%~96.0%, 84.0%~97.4% and 83.0%~97.8% respectively.Part â…¢: A gas chromatography/mass spectrometric method was developed to confirm CAP. A relatively simple and cheap mass-selective detector with electron impact ionization was selected. Scan mode was employed to select diagnostic ions and SIM mode was employed to confirm CAP. The diagnostic ions are m/z 225 and 208. The limit of SIM was 5 g/kg. The GC/MS method proposed in this study does not necessarily provide quantitative information.Screening with an ELISA procedure followed by quantitation with GC and confirmation with GC/MS was found to be an effective strategy for the regulatory control of CAP in aquatic products.