Simultaneous determination of 17 sulfonamide residues in porcine meat, kidney and liver by solid-phase extraction and liquid chromatography-tandem mass spectrometry

A precise and reliable method, using normal phase cartridge clean-up and liquid chromatography coupled with tandem mass spectrometry has been developed for measuring the residues of 17 sulfonamides in porcine tissues included in meat, liver and kidney. The parameters of mass spectrometer were optimized by continuous direct injection through a syringe pump. The composition and additives for mobile phases were also evaluated and the optimum one was methanol-water containing 0.1% formic acid. A liquid-liquid extraction and Sep-Pak silica clean-up procedure was developed for sample preparation. The method was validated and found to be satisfactorily linear, selective and robust. Recoveries ranged from 52 to 120% for all compounds at three different spiking levels and the limit of detections (LODs) ranged from 0.01 to 1.0 ng/g depending on various compounds.