ANALYSIS OF SULFONAMIDE RESIDUES IN REAL HONEY SAMPLES USING LIQUID CHROMATOGRAPHY WITH FLUORESCENCE AND TANDEM MASS SPECTROMETRY DETECTION

Abstract

This paper presents new reversed phase liquid chromatographic methods (HPLC-FLD and LC-MS/MS) for the quantification of sulfonamides in spiked and incurred honey samples. The sample preparation was optimized using Oasis HLB (hydrophilic–lipophilic balance) solid-phase extraction (SPE) cartridge. Elutions of sulfonamides were carried out under acidic, neutral, and basic conditions using methanol. Recoveries under acid condition were in the range from 66.8–90%, which were approximately 10% higher than those obtained under other conditions. The sample clean-up was also tested using Strata-XL cartridges. The HPLC-FLD separation was performed using a Varian C18 column and a ternary (methanol-acetonitrile-phosphate buffer, pH 5) mobile phase resulting good selectivity for the determination. The robustness of the ternary gradient method was evaluated by computer simulation (DryLab). LC-MS/MS separation was carried out on a Kinetex XB core-shell type HPLC column that enabled a low limit of detection (0.01–0.5 µg/kg) and faster separation (6 min). The developed methods were validated in accordance with the European Union Commission Decision 2002/657/EC and were applied successfully for more than four hundred honey samples (under a national monitoring program). The concentrations of sulfadimethoxine, sulfachloropyridazine, and trimethoprim residues in samples were found in a concentration range from 0.03 up to 686 µg/kg.