Pre-study and in-study validation of an ultra-high pressure LC method coupled to tandem mass spectrometry for off-line determination of oxytetracycline in nasal secretions of healthy pigs.

In order to quantify oxytetracycline (OTC) in nasal secretions of healthy pigs after intramuscular injection of OTC at doses of 10, 20 and 40 mg/kg bodyweight, an original method based on ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed and fully validated. Sample preparation consisted in protein precipitation preceded by the addition of a releasing protein reagent. Metacycline (MTC) was used as internal standard.