Screening of antimicrobials in animal-derived foods with desorption corona beam ionization (DCBI) mass spectrometry.

The relatively new technique, desorption corona beam ionization (DCBI), was coupled with an ion-trap mass spectrometer for the rapid detection of 10 antimicrobials in animal-derived food. Under positive ion mode, 10 common antimicrobials were identified without prior sample preparation. With simple pre-treatment, semi-quantification based on peak area was achieved. There was a good correlation (R2 > 0.99) in the rational linear ranges (1-3 orders of magnitude) for all 10 target analytes. Compared with a conventional liquid chromatographic method, the DCBI-MS method was highly sensitive; e.g., roxithromycin was detected at 0.02 µg/g, whereas the value was 0.2 mg/kg in the European Union Commission Regulation (No 37/2010) and 0.3 μg/mL in a recently reported LC method. The proposed method allowed for the simple, rapid, sensitive and specific detection of antimicrobials in animal-derived foods. Our approach could be used for other atmospheric pressure chemical ionization (APCI) related ambient mass spectrometry methods to detect other compounds.