▎ 摘　　要

Graphene quantum dots and magnetite nanoparticles were embedded in molecularly imprinted polymer (GQDs@Fe3O4/MIP) to develop a magnetic nanocomposite fluorescent probe that could enrich and detect trace ceftazidime in milk in conjunction with an optosensor. Graphene quantum dots enhanced the sensitivity of the optosensor and the specificity of the molecularly imprinted polymer reinforced the selectivity of the nano composite probe. The incorporated magnetite nanoparticles increased enrichment of the target analyte so that a smaller volume of detecting solution could be used. The developed probe was characterized and the preparation procedure and detection conditions were optimized. In the optimum conditions, linearity was in the range of 0.10-10.0 mu g L-1 and the limit of detection was 0.05 mu g L-1. The developed system was utilized to detect ceftazidime in milk samples. Recoveries were in the range of 90.7-99.2% with RSD below 6% and the obtained results agreed well those obtained with chromatographic technique. However, the developed optosensor exhibited better sensitivity, was faster and easier to operate and can be modified for the enrichment and detection of other target analytes in various sample matrices.