An electrochemiluminescence energy resonance transfer system for highly sensitive detection of brombuterol

In this work, an electrochemiluminescence resonance energy transfer (ECL-RET) system was established based on the modified graphite phase carbon nitride to detect brombuterol residues in food. The ultrasonic-assisted acidification exfoliation modification improved the conductivity and specific surface area of the graphite phase carbon nitride (g-C₃N₄). In addition, the carboxylated g-C₃N₄ nanosheets as ECL donors and the Au-Ag alloy nanoparticles as ECL acceptors could respectively directly carry antigen and antibody. Therefore, the trouble of introducing additional bridge molecules was avoided. A competitive immunoassay strategy was used for the detection of brombuterol, where brombuterol in the sample would compete with the coating antigen for the limited binding sites on antibody. The proposed ECL immunosensor for brombuterol detection exhibited high sensitivity with a wide linear range from 0.001 ng mL^-1 to 1000 ng mL^-1 and a low detection limit at 0.31 pg mL^-1. This work adopts a very simple way to design the sensor without losing its sensitivity, bringing convenience to its possible future applications.