A quantitative method for the detection of sulfonamide residues in meat and milk samples with a high-performance thin-layer chromatographic method.

Sulfonamides are widely used in veterinary medicine for prophylactic purposes and for the treatment of various infections of food-producing animals. This means that residues of these drugs and their possible metabolites may occur in food of animal origin. In Belgium, a zero tolerance level for sulfonamides in edible animal tissues has been set. In order to check this zero level on a routine basis, a rapid and sensitive method has to be available. For this purpose, a quantitative high-performance thin-layer chromatographic (HPTLC) method for the detection of sulfonamide residues in animal tissue and milk samples has been developed. The sample preparation consists of a liquid extraction followed by a solid phase extraction (SPE) on disposable columns for the meat samples and a matrix solid phase dispersion (MSPD) for the milk samples. A three-multiple development chromatographic system is used for the separation and a derivatization with fluorescamine decreases the minimal detectable quantity per spot from 1.42 to 0.32 ng. The limit of quantification is 4 micrograms/kg for milk and meat samples.