Synthesis of Fragment-Imprinted Microspheres of 2,6-Dichloropyrimidine as Templates and Determination of Sulfonamides in Milk Samples

Fragment-imprinted microspheres (FIMs) were prepared by suspension polymerization. 2,6-Dichloropyrimidine was used as the template molecule instead of sulfonamides, methacrylic acid and styrene were the mixed functional monomers, ethylene dimethacrylate was the crosslinking agent, and azodiisobutyronitrile was the initiator. The optimum conditions were obtained by an orthogonal experiment. The maximum adsorption was obtained under the optimum conditions. The adsorption by FIMs was 7.02 mg g−1, whereas the adsorption by non-FIMs was 5.41 mg g−1. A method for the simultaneous determination of five sulfonamides from milk samples by fragment imprinted-solid phase extraction coupled with HPLC was developed. The recoveries for the five sulfonamide extractions were 89.7–97.6 % with relative standard deviations of 1.79–3.02 %, indicating the suitability of the prepared FIMs for sulfonamide extraction.