Trace determination of sulfonamides residues in meat with a combination of solid-phase microextraction and liquid chromatography-mass spectrometry.

An integrated method of combining solid-phase microextraction (SPME) with liquid chromatography-mass spectrometry (LC-MS) was evaluated for determination trace amount of sulfonamides in meat products. Eight commonly used sulfonamides, sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMT), sulfamonomethoxine (SMMX), sulfamethoxazole (SMXZ), sulfaquinoxaline (SQX) and sulfadimethoxine (SDMX), were investigated in this study. Chromatography was performed on a C(18) reversed-phase column using an isocratic acetonitrile in water as the mobile phase. Fiber coated with a 65mum thickness of polydimethylsiloxane/divinylbenzene (PDMS/DVB) was used to extract sulfonamides at optimum conditions. Analytes were desorbed with static desorption in an SPME-HPLC desorbed chamber for 15min and then determined by LC-MS. The detection limits of these sulfonamides in pork were from 16mugkg(-1) (SMT) to 39mugkg(-1) (SMMX). According to the analysis, the linear range was from 50 to 2000mugkg(-1) with relative standard deviation (R.S.D.s) value below 15% (intra-day) and 19% (inter-day). The proposed method was tested by analyzing meats from a local market for sulfonamides residues. Some sulfonamides in our study were detected in the meat samples. The concentration of these residual sulfonamides ranged from 66mugkg(-1) (SDZ) to 157mugkg(-1) (SQX) in a chicken sample. The results demonstrate that the SPME-LC-MS system is highly effective in analyzing trace sulfonamides in meat products.