In the initial study, the mixture of 15 studied sulfonamide standards, with and without derivatization by fluorescamine, were separated by long C-18 column. The higher retention behavior observed when the mixture of sulfonamide standards was injected after derivation with fluorescamine, as can also be deduced from Refs. [9,20]. This higher retention provoked us to use the short C-18 column for the online extraction of sulfonamide residues from honey matrix.