Comparison of HPLC–DAD and LC–MS Techniques for the Determination of Tetracyclines in Medicated Feeds Using One Extraction Protocol

Abstract Four antibiotics, oxytetracycline, tetracycline, doxycycline, and chlortetracycline were separated quantified in medicated feed. Tetracyclines from feed samples extracted with 0.01 M citric buffer acetonitrile (pH 3.0) further purified 0.45 µm syringe filters. The extract was on commercial RP-C18 column analyzing using liquid chromatograph (LC) two different detectors: diode array detector (DAD) mass spectrometry (MS). These methods provided average recoveries 72.2 to 101.8% for high pressure chromatography (HPLC) detection 45.6 87.0% spectrometry. limit of ranged 4.2 10.7 mg kg ?1 HPLC–DAD 5.6 10.8 LC–MS. Our experiment showed that the same extraction mixture we do not obtain recovery values analyzed compounds techniques such as DAD MS.