Simultaneous determination of six quinolones in pig muscle by liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry

An LC-MS method is described for the confirmation of six quinolones (enrofloxacine, ciprofloxacine, marbofloxacine, danofloxacine, sarafloxacine and difloxacine) in pig muscle. The quinolones were extracted from muscle (2 g) with phosphate buffer (pH 7.4). After centrifugation, the extract was purified on a C-18 solid-phase extraction cartridge. Samples were analysed by LC with gradient elution on a C-18 column and detected by MS via an atmospheric pressure chemical ionisation interface. For each compound, an intense pseudo-molecular ion [M+H](+) is obtained. The assay is specific and reproducible and allows the confirmation of the six quinolones at the 7.5 mu g kg(-1) level in pig muscle.