Applications of a Novel Sample Preparation Method for the Determination of Sulfonamides in Edible Meat by CZE

A simple, rapid and reliable method based on SPE clean-up and CZE separation was validated for the trace determination of sulfonamides (SAs) in meat. Acetonitrile was used for the extraction of SAs (sulfamethoxazole, sulfamethazine, sulfamerazine, and sulfadimethoxine) from the samples and 1-propanol was used for the denaturing of the proteins present in the sample matrix. SPE procedure was employed for the clean-up and pre-concentration of SAs prior to CZE analysis. Complete separation was achieved by using 45 mmol L-1 phosphate buffer (pH = 6.3) at an applied voltage of 20 kV. Overall obtained recoveries were from 83.3 to 94.5% for the SAs. The detection limit of each sulfonamide ranges from 4 to 6 mu g kg(-1). The presented one step SPE clean-up method is highly applicable for the determination of the SAs at a residue level below the maximum residue limit.