Electron-capture detection of chloramphenicol using a heptafluorobutyrate derivative. Application to residues in milk.

A gas-liquid chromatographic method is described for the quantitation of the halogenated heptafluorobutyrate derivative of chloramphenicol, using electron-capture detection. Treatment of the chromatographic support with heptafluorobutyric anhydride permits a linear recovery even at very low concentrations. After extraction using acetonitrile followed by a convenient cleaning procedure, this method can be applied to the determination of trace amounts of chloramphenicol in milk. Interfering peaks have been observed on the chromatograms of some control milk samples. These determine the detection limit of 50 ppb.