In　this　paper,　CdS　quantum　dots　(QDs)　were　synthesized.　Positively　charged　poly(diallyldimethylammonium　chloride)　(PDDA)　and　negatively　charged　CdS　quantum　dots　were　sequentially　adsorbed　on　the　surface　of　graphene　oxide　(GO).　The　nano-luminescent　materials　GO-QDs　were　prepared　and　characterized　by　UV-Vis　absorption　spectroscopy,　fluorescence　spectroscopy　and　transmission　electron　microscopy.　The　GO-QDs　were　then　modified　on　the　surface　of　glassy　carbon　electrode　(GCE).　Chloramphenicol　aptamer　(apt)　of　5＇-end　modified　biotin　hybridized　with　the　aptamer　complementary　strand　(cDNA)　of　5＇-end　modified　amino　group　into　double-stranded　DNA　(dsDNA).　The　double-stranded　DNA　was　bonded　onto　the　surface　of　GO-QDs　modified　electrode.　When　the　electrode　was　incubated　with　streptavidin　-　labeled　horseradish　peroxidase　(SA-HRP),　the　biotin　modified　at　the　end　of　the　chloramphenicol　aptatner　can　specifically　bind　directly　to　the　streptavidin　labeled　HRP.　Therefore,　HRP　was　bonded　to　the　surface　of　the　electrode.　Hydrogen　peroxide　was　used　as　the　co-reactant　of　the　QDs.　HRP　can　thereby　consume　hydrogen　peroxide　and　can　weaken　the　electrochemiluminescence　intensity.　Chloramphenicol　in　solution　can　specifically　bind　to　the　aptamer　to　form　a　composite　and　to　unwind　the　dsDNA.　Then　the　composite　was　detached　from　the　surface　of　the　electrode.　HRP　also　left　the　electrode　surface　along　with　the　aptamer,　so　that　the　electrochemiluminescence　signal　was　significantly　enhanced.　The　electrochemiluminescence　intensity　of　the　sensor　showed　a　linear　correlation　with　the　logarithm　of　chloramphenicol　concentration.　The　linear　range　was　1.0　x　10(-12)-1.0　x　10(-7)　M,　the　detection　limit　is　0.5　pM.　The　reproducibility,　stability　and　specificity　of　the　sensor　were　also　studied.　The　sensor　was　used　for　the　determination　of　chloramphenicol　in　samples　and　satisfactory　results　were　obtained.　(C)　2020　Elsevier　B.V.　All　rights　reserved.