Thin　antimony　oxide　covered　AuSb　alloy　electrode　was　firstly　found　to　be　an　excellent　cold　cathode　for　generating　hot　electrons　during　cathodic　pulse　polarization.　Owing　to　the　injection　of　hot　electrons　and　the　subsequent　generation　of　hydrated　electrons,　fluorescein　iso-thiocyanate　(FITC)　that　cannot　be　excited　in　common　ECL　was　cathodically　excited　at　the　alloy　electrode.　Self-assembled　thiol　monolayers　were　formed　on　the　electrode　surface　due　to　the　presence　of　Au　in　the　alloy,　to　which　strepavidin　was　covalently　bound,　and　then　biotinylated　antibody　was　immobilized　through　the　strepavidin-biotin　interaction.　As　a　simple　model,　an　immunosensor　for　the　detection　of　human　IgG　(hIgG)　using　FITC　as　labeling　agent　was　fabricated.　ECL　signals　were　responsive　to　the　amount　of　hIgG　bounded　to　the　immunosensor.　The　ECL　intensity　was　linearly　changed　with　the　logarithm　of　hIgG　concentration　in　the　range　of　1.0-1000　ng　mL(-1),　and　the　detection　limit　was　ca.　0.3　ng　mL(-1)　(S/N=3).　The　proposed　immunosensor　showed　a　broad　linear　range　(three　magnitudes),　good　reproducibility　and　stability,　which　is　promising　in　detecting　FITC-based　labels　in　various　types　of　bioaffinity　assays.　(C)　2010　Elsevier　B.V.　All　rights　reserved.