The development of antibiotic resistance in bacteria has been attributed to the overuse of antimicrobials in human medicine. Another route by which humans are exposed to antibiotics is through the animal foods we eat. In modern agricultural practice, veterinary drugs are being used on a large scale, administered for treating infection or prophylactically to prevent infection.

This paper describes the principles, the current technology and the applications of HPLC and tandem mass spectrometry (LC