▎ 摘　　要

Tiamulin (TML) is a pleuromutilin antibiotic and mainly used to treat pulmonary and gastrointestinal infections. However, excessive use of TML can bring health threats to consumers. In this work, a label-free electrochemical immunosensor was proposed for sensitive detection of TML in pork and pork liver. Silver nanoparticles (AgNPs) were synthesized in situ on graphene oxide (GO), in which GO acted as a car-rier for loading more AgNPs and AgNPs exhibited both strong conductivity and good redox property. In addition, staphylococcal protein A (SPA) was applied to oriented immobilization of fragment crystalliz-able (Fc) region of the TML monoclonal antibody. Under the optimal condition, the developed electro-chemical immunosensor exhibited a good linear response with a concentration of TML ranging from 0.05 ng mL(-1) to 100 ng mL(-1) and the limit of detection (LOD) was 0.04 ng mL(-1). Furthermore, the designed immunosensor was applied to detect TML in real samples with a good accuracy. Therefore, the label-free electrochemical immunosensor could be used as a potential method to detect TML and other antibiotic residues in animal derived foods. (C) 2021 Elsevier B.V. All rights reserved.