The European Union prohibits the use of chloramphenicol (CAP) as a veterinary drug for food producing animals. For this reason a rapid and sensitive confirmatory method for the identification and quantification of CAP in milk and milk products has been developed using the API 3000 LC/MS/MS System. Although many analytical procedures are described in the literature, the presented method has the advantages of high recovery and short analysis time. The method was validated according to the EU Commission Decision 2002/657/EC.
Chloramphenicol (Figure 1) is a broad-spectrum antibiotic previously used in veterinary medicine because of its broad range of activity and its low cost. Chloramphenicol is primarily bacteriostatic. CAP binds to the 50S subunit of the ribosome and inhibits bacterial protein synthesis. It has a wide spectrum of activity against gram-positive and gram-negative cocci and bacilli, including anaerobes.
Because of the side effects in humans, particularly dose independent fatal aplastic anemia, the use of CAP for the treatment of food-producing animals is prohibited in several countries (e.g. European Union, Canada, United States, and most Asian counties). The Commission Decision 2002/657/EC necessitates control of CAP residues in edible tissues, milk, and milk products.
Methods to detect CAP residues in biological matrices, especially in milk, include immunoassays1 and mass spectrometry in combination with GC24 and HPLC5,6. Immunological methods are suitable for screening purposes, whereas mass spectrometric methods are utilized for confirmation. Methods for the determination of CAP residues using GC/MS require additional chemistry steps, such as silylation of CAP, before the samples can be analyzed. LC/MS, on the other hand, requires no derivatization and can be direc