[Synthesis and application of a magnetic spiramycin-templated molecularly imprinted nanoparticle adsorbent]

A magnetic spiramycin-templated molecularly imprinted nanoparticle adsorbent is described. It was synthesized by choosing Fe₃O₄ nanoparticles as the core, and then modified with acrylic acid, followed by the addition of spiramycin as a template molecule, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. Finally, the adsorbent was prepared via surface radical polymerization. The adsorbent demonstrated effective enrichment for four macrolide antibiotics (MA) including spiramycin, josamycin, tilmicosin, and tylosin tartrate, whose enrichment factors were 310, 118, 758, and 72, respectively. Its selectivity toward the trace MA was obviously higher than that of the common C₁₈ adsorbent. In addition, the adsorbent also showed favorable reusability (at least six times). A corresponding analytical method for MA was established by subjecting the adsorbent to high-performance liquid chromatography with ultraviolet absorbance. For the above four model MAs, the limits of detection were in the range of 0.53-2.75 μg/L, and the limits of quantitation were in the range of 1.78-9.16 μg/L. The recoveries of the method were in the range of 80.78%-123.02% for three spiked levels of 50, 100 and 150 μg/L, and the relative standard deviation was less than 15.8% (n=5). The method was used for the determination of the four MAs above in honey.