Fast Determination of Residual Sulfonamides in Milk by In-Tube Solid-Phase Microextraction Coupled with Capillary Electrophoresis-Laser Induced Fluorescence

A fast, feasible, eco-friendly method for determination of sulfonamides using in-tube solid-phase microextraction (IT-SPME) coupled with capillary electrophoresis-laser induced fluorescence was developed. The graphene-embedded porous polymer monolithic column prepared via in-situ UV polymerization was proposed as the IT-SPME column. The method was applied to determine residual sulfonamides in a real milk sample, and an amount of 3.7 ng mL−1 sulfamethazine was detected, which was much lower than the maximum residue limit.