Potential-Resolved Electrochemiluminescence Multiplex Immunoassay for Florfenicol and Chloramphenicol in a Single Sample

The simultaneous detection of multiple antibiotic residues in food is of great significance for food safety. In this work, a novel dual-potential electrochemiluminescence (ECL) immunoassay was designed for the simultaneous detection of chloramphenicol and fluorfenicol residues in food. Ru@MOF was used as an anodic probe, and SnS₂ QDs-PEI-Au-MoS₂ was used as a cathodic probe. Notably, the coreactant for both luminophores was K₂S₂O₈, avoiding interactions caused by different kinds of coreactants. Au nanoparticles functionalized with a nitrogen- and sulfur-doped graphene oxide-modified glassy carbon electrode to improve the electron transfer efficiency and provide a larger surface area for immobilization of antigen. The linear range for the detection of florfenicol was determined to be 0.1-1000 ng mL⁻¹ with a detection limit of 0.03 ng mL⁻¹, and the linear range for the detection of chloramphenicol was 0.01-1000 ng mL⁻¹ with a detection limit of 3.2 pg mL⁻¹ by recording the ECL responses at two different excitation potentials. The proposed immunoassay achieved a more stable recovery in the detection of actual samples and provided a new analytical method for the simultaneous detection of florfenicol and chloramphenicol residues with high sensitivity and specificity.