Determination of sulfonamide residues in milk by on-line microdialysis and HPLC

A technique for the simultaneous determination of sulfonamides in milk was studied by using a home-made microdialysis system on-line to high-performance liquid chromatography. Six sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfadimethoxine, and sulfamethoxazole) in milk were isolated by a hollow dialysis fiber prior to chromatographic determination.. The results shows 2-5 fold enrichments and the detection limits in sub-mugL(-1) levels. As the milk sample was spiked with the six sulfonamides, in the concentration ranges between 0.005 and 10 mgL(-1), recoveries ranging from 97.8% to 100.4% were obtained, and the regression coefficients >0.995. The proposed method provides a simple, fast, and eco-friendly procedure for isolating and determining sulfonamides in milk samples.