A Novel immunofluorescence capillary electrophoresis assay system for the determination of chloramphenicol in milk

An immunofluorescence capillary electrophoresis technique is described for the detection of chloramphenicol where the analyte was allowed to compete with a chloramphenicolfluorescein conjugate for binding to polyclonal anti‐chloramphenicol antibody. The bound and unbound forms of the chloramphenicol‐fluorescein conjugate were then analyzed by capillary zone electrophoresis with laser‐induced fluorescence detection, which permitted direct quantitation of the extent of immunocomplex formation. The amount of unbound conjugate in the reaction mixture was proportional to the quantity of chloramphenicol in the sample. Using this assay, it was possible to detect concentrations as low as 0.1–0.5 ng ml^‐1 of chloramphenicol in a standard buffer and at least 01 ng ml^‐1 of chloramphenicol in milk after extraction with ethyl acetate using a simple protocol. This highly sensitive procedure was rapid, requiring less than 30min to complete. The immunofluorescence capillary electrophoresis system should be similarly applicable to the assay of a wide variety of analytes.