▎ 摘　　要

A hierarchical composite nanoprobe was fabricated and utilized to detect sulfadimethoxine as a specific and sensitive fluorescent sensor. The hierarchical composite probe integrated graphene quantum dots and porous carbon in molecularly imprinted polymer (GQDs@PC@MIP). The quantitative analysis of sulfadimethoxine was obtained by measuring the quenching of the fluorescence response of the nanoprobe when sulfadimethoxine bound with the selective recognition sites. The fluorescence emission of the composite nanoprobe decreased linearly from 0.10 to 25.0 mu g L-1 and the limit of detection was 0.03 mu g L-1. The recognition sites were highly specific for the sulfadimethoxine molecule with an imprinting factor of 8.75. The developed hierarchical composite nanoprobe was used to determine sulfadimethoxine in milk. Recoveries between 86.8 and 98.9% were achieved with RSDs lower than 5%. The developed nano-optosensor showed good accuracy, providing results that were in good agreement with HPLC analysis. However, the developed assay showed better sensitivity, required simple and cost-effective instruments and was more convenient to operate.