Simultaneous Determination of Seventeen Sulfonamide Residues in Chickens by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

A liquid chromatography-electrospray tandem mass spectrometry LC-MS/MS for the simultaneous determination of seventeen commonly used sulfonamide SA residues in chickens has been developed. Stable isotopic compound C-13(6)-sulfamethazine was used as internal standard. Multi-reaction monitoring mode was employed for the quantitative determination. The separation was performed on a Capcell Pak C-8 DD column 150 mm x 2. 0 mm i. d. 5 mu m with a gradient system of water containing 0. 2% formic acid-methanol containing 0. 2% formic acid as mobile phase at a flow rate of 0. 2 mL/min. Samples were prepared by homogenizing the chicken extracting with acetonitrile defatting with n-hexane and cleaning-up with Sep-Pak Silica solid-phase extraction. The detection limits of 0. 02 - 1 mu g/kg proved to be much better than the previously reported ones. Average recoveries of seventeen SAs spiked at the levels of 1 5 10 mu g/kg ranged from 52.3% to 124.9% with relative standard deviations between 1. 0% and 17. 6%. Intra-day and inter-day variations of the method were all with in the acceptable ranges. The results demonstrated that the method is simple accurate and suitable for the identification and quantification of these sulfonamide residues in chickens.