Objective  A molecularly imprinted polymer adsorbent with specific recognition for mycophenolic acid was synthesized for purification, enrichment and analysis of mycophenolic acid in silage.

Method  Using silica gel modified by γ-methacryloxy propyl trimethoxy silane (γ-MPS) as the carrier, mycophenolate mofetil as the virtual template, the surface molecularly imprinted polymers were prepared on silica gel. The prepared materials were characterized by scanning electron microscopy, and the adsorption characteristics were evaluated by equilibrium adsorption test. The solid phase extraction-high performance liquid chromatography (HPLC) method based on the synthesized molecularly imprinted polymer was established to detect the mycophenolic acid in silage.

Result  The modified silica gel surface was successfully wrapped with a layer of molecularly imprinted polymer. The static adsorption test showed that the saturated adsorption capacity of the imprinted material was 4.5 mg/g, and the dynamic adsorption test showed that the adsorption rate of the material was fast, and the adsorption equilibrium was reached within 60 min. The HPLC method was established using the imprinted material as the solid phase extraction adsorbent. The recovery rates of mycopholanolic acid were in the range of 76.0% to 81.2%, the relative standard deviation was less than 7%, and the detection limit was 60 μg/kg.

Conclusion  The prepared mycophenolic acid molecularly imprinted polymer on the surface of silica gel can specifically adsorb mycophenolic acid. The established molecularly imprinted polymer solid phase extraction-HPLC method can be used for daily determination of mycophenolic acid in silage to know the situation of mycotoxin contamination in feed. The results can provide guidance for quality safety control of silage.