▎ 摘　　要

NOVELTY - An oxytetracycline detecting method involves preparing oxidation graphene - gold nanoparticles composite, preparing BSA-OTC complex by preparing cyclic probe followed by taking a glassy carbon electrode, first polished with alumina slurry until the mirror, and the secondary water repeatedly with PBS Rinse, after electrode immersed in graphene oxide, adding 1 mu M OTC aptamers, incubated for 2 h, washing with PBS, placing into ring probe, adding BSA, Phi29DNA polymerase, 2 mu l Phi29DNA polymerase buffer, adding methylene blue, detecting by using aptamer electrode. USE - Method for detecting oxytetracycline. DETAILED DESCRIPTION - An oxytetracycline detecting method involves preparing preparing graphite oxide - gold nanoparticlecomplex by polishing glassy carbon electrode with alumina slurry, rinsing with water, dropping 20 mu L 1.0 mg.mL-1 oxide graphene on the electrode, drying after the electrode immersed in 10 mL 2.8 mmol.L-1 gold chloride trihydrate, 0.1 molL-1 sulfuric acid solution, cyclic voltammetry electrochemical total reduction to obtain graphene - gold complex solution. BSA-OTC complex by preparing cyclic probe by taking 3 mu l padlock probe, placing in sterile centrifuge tube, adding 6 mu l T 4 DNA ligase buffer solution, 50 mu l sterilization water, shock evenly, with raw materials closed, placing into tube at 95 degrees C for 10 minutes, constant temperature of 37 degrees C for 2 hours, so that hybridization complete, adding 2 mu l T4DNA ligase, sealing film sealing, at constant temperature of 16 degrees C for 2h, connected to the padlock probe, 65 degrees C for 20 minutes for T4DNA ligase denaturation, adding 1 mu l exonuclease I, incubating at 37-80 degrees C after the hydrolysis probe connector C thermostat for 20minutes make exonuclease I denaturation give cyclic probe, followed by taking a glassy carbon electrode, first polished with alumina slurry until the mirror, and the secondary water repeatedly with PBS Rinse, after electrode immersed in graphene oxide, maintaining for 3hours, secondary rinsing with water rinse, adding BSA-OTC conjugates dropwise at the electrode surface, room temperature for 150 min, so that BSA-OTC complex completely immobilized on the electrode, resulting electrode after PBS washing buffer and sufficiently stirred, to be detected into oxytetracycline, adding 1 mu M OTC aptamers, incubated for 2 h, washing with PBS, placing into ring probe, adding BSA, Phi29DNA polymerase, 2 mu l Phi29DNA polymerase buffer, at 37 degrees C for 1.5 hours, adding 4 mM methylene blue, detecting by using aptamer electrode, where the nucleotide sequence of the padlock probe is SEQ ID NO: 3, nucleotide sequence as a probe connected is SEQ ID NO: 4 and nucleotide sequence of the nucleic acid aptamer OTC is SEQ ID ?O: 2, and the sequence is not defined.