Preparation of magnetic molecularly imprinted polymers for selective extraction of xylazine in milk

Magnetic molecularly imprinted polymers (MMIPs) were prepared by surface precipitation polymerisation, which used xylazine as its template molecule and Fe3O4 as its support. The characterisation analysis and adsorption experiments of MMIPs were carried out. At the same time, promethazine, chlorpromazine, trifluoperazine, acepromazine and perphenazine were selected as structural analogues for selective experiments. The results showed MMIPs were successfully prepared with small particle size, excellent magnetic and thermal stability, high adsorption capacity and selectivity for xylazine. The maximum adsorption capacity of MMIPs for xylazine was 4.2017 mg g(-1), and the adsorption reached binding equilibrium within 30 min. The magnetic solid phase extraction (MSPE) based on MMIPs and traditional solid phase extraction (SPE) based on SPE column for xylazine in milk samples were compared and xylazine was analysed by HPLC. Although the difference between the two SPE methods was not significant, the MSPE method procedure took only about 35 min, which was faster than the traditional SPE method (>100 min), and the MSPE method had lower LOD (2.62 ng mL(-1)). MSPE has the advantages of simple operation, short extraction time, low cost and friendly to the environment, it has good application potential in the detection of xylazine in milk samples.