Determination of sulfonamides in honey by liquid chromatography-tandem mass spectrometry

A simple and rapid analytical method was developed for the determination of residues of seven sulfonamide antibiotics in honey. Sample preparation consisted of acid hydrolysis to release sugar-bound sulfonamides. After filtration, acidified honey solutions were injected directly into a liquid chromatograph-tandem mass spectrometer (LC-MS/MS) system. Using gradient elution programming, analyte extraction and sample cleanup were automated. A six-port valve system was utilized to divert eluent from the extraction column into the MS/MS after the bulk of the honey matrix had been selectively removed. Minimal contamination of the MS source chamber was observed even after the injection of over 600 honey samples. Using internal standard quantitation, excellent accuracy and good precision were obtained. The method detection limits for the sulfonamides studied were found to range from 0.5 to 2 μg kg−1.