Determination of selenium in food and environmental samples using a gold nanocages/fluorinated graphene nanocomposite modified electrode

•Synthesized a gold nanocages/fluorinated graphene nanocomposite.•A novel electrochemical method was developed for the detection of selenium.•This method exhibited wide linear range, low LOD, excellent selectivity, and in good agreement with AFS.•This electrochemical method was successfully applied to selenium determination in agricultural food and environmental samples.