Determination of sulfonamides in food samples by membrane-protected micro-solid phase extraction coupled with high performance liquid chromatography.

In the present study, a simple and sensitive extraction method based on polypropylene membrane-protected micro-solid phase extraction (MP-μ-SPE) has been developed for analysis of sulfonamides in food samples. Poly (methacrylic acid-ethylene glycol dimethacrylate) (p-MAA-EDMA) was synthesized using orthogonal array experimental design, optimized with three factors at four levels and evaluated on yield, hydrophobic and cation-exchange properties. The optimized p-MAA-EDMA was then employed as the sorbent in the MP-μ-SPE for extraction of sulfonamides from milk and chicken muscle samples, followed by high performance liquid chromatographic analysis with ultraviolet detection. Under optimized extraction conditions, good linearities (0.010-1.0 μg mL(-1) with r(2)>0.9900), low limits of detection (0.38-0.62 ng mL(-1)), and acceptable intra-day (2.7-13.7%) and inter-day (6.7-15.2%) relative standard deviations were obtained. It was demonstrated to be an effective approach to handle semi-solid/solid samples with good resistance to interference from "dirty" samples.