Study on the determination of chloramphnicol residues in milk by fluorescent derivatization with fluorescamine

A new method for the determination of chloramphnicol residues in milk by fluorescent after derivatization with fluorescamine has been established. Chloramphenicol in milk samples was extracted by ethyl acetate, and then evaporated to dryness. Residues were dissolved in NaCl solution and fats were cemoved using n-hexane, and then chloramphenicol was re-extracted into the medium of ethyl acetate. Ethyl acetate was removed by insufflating N_2. Chloramphenicol was reduced and derivatized with fluorescamine. The linear range for a chloramphenicol derivative is 12.5～500 μg/mL, the recovery is 81%～87%, and the relative standard deviation is 3.9%～8.4%. The lowest determination limit for chloramphenicol residue in milk is 2.5 ng/mL. This method is simple and can be used for the selective determination of trace chloramphenical in milk.