Application of liquid chromatography–electrospray ionization tandem mass spectrometry to the detection of 10 sulfonamides in honey

Liquid chromatography (LC) in combination with tandem mass spectrometry (MS–MS) has been applied to the separation and detection of 10 different sulfonamides in honey. The methodology encompasses a simple hydrolysis of the honey sample to liberate sugar-bound sulfonamides followed by liquid–liquid extraction of the 10 analytes, filtration, and analysis by LC–MS–MS. Conditions for reversed-phase LC and electrospray ionization (ESI) MS–MS in the positive ion mode were optimized for the 10 compounds under study, monitoring two characteristic mass transitions simultaneously for each analyte. The procedure is a qualitative confirmatory method for 10 sulfonamides at the low μg/kg level in honey. Typical recoveries of the analytes in honey ranged from 44 to 73% at a fortification level of 50 μg/kg. This study also addresses the issue of matrix-induced suppression of ionization, an effect often encountered in trace residue analysis of food matrices using LC–ESI-MS–MS based methods.