▎ 摘　　要

NOVELTY - Preparing graphene/zinc oxide/indium tin oxide electrode, comprises e.g. using distilled water as solvent for preparing zinc nitrate solution, hexamethylene tetramine solution, aqueous ammonia solution and polyetherimide solution, mixing, and stirring to obtain hydrothermal reaction solution, adding the hydrothermal reaction solution into a reaction kettle, covering upper kettle cover, reacting, then removing and cooling to obtain zinc oxide, opening the reaction kettle, cleaning the material and passing the filtered zinc oxide into the culture dish and drying in lower drying box. USE - The graphene/zinc oxide/indium tin oxide electrode is useful in biosensors (claimed). ADVANTAGE - The electrode has high sensitivity, good selectivity, repeatability, stability, and solves low sensitivity of the existing materials for detecting levodopa in biosensor. DETAILED DESCRIPTION - Preparing graphene/zinc oxide/indium tin oxide electrode, comprises (i) using distilled water as solvent for preparing 0.03-0.07 mol/l zinc nitrate solution, 0.03-0.07 mol/l hexamethylene tetramine solution, 0.03-0.07 mol/l aqueous ammonia solution and 3-7 mmol/l polyetherimide solution, uniformly mixing, and magnetically stirring at 450-550 rotations/minute for 3-5 minutes to obtain hydrothermal reaction solution; (ii) (a) adding the hydrothermal reaction solution into a reaction kettle, covering upper kettle cover, reacting at 90-120 degrees C for 10-14 hours, then removing and cooling to room temperature in air to obtain zinc oxide, opening the reaction kettle, cleaning the material with distilled water and passing the filtered zinc oxide into the culture dish, drying in lower drying box 70-90 degrees C for 1-3 hours; (b) mixing 0.01-0.03 g zinc oxide and 20 ml deionized water to obtain zinc oxide nano flower suspension, ultrasonically washing indium tin oxide into acetone solution, ethanol solution and deionized water for 20 minutes, cooling to room temperature and drying the six pieces of indium tin oxide conductive glass fixed on the spraying device heating plate covering with transparent tape to indium tin oxide conductive glass clip on one side of the electrode, ensuring cleaning the electrode line and indium tin oxide conductive glass directly; (iii) uniformly dispersing zinc oxide nano flower suspension in the spray gun using automatic spraying for preparing indium tin oxide zinc oxide electrode, and whole spraying process has inlet air pressure of 10 psi, distance of the nozzle to the indium tin oxide is 15 cm, heating plate temperature of 100 degrees C, spraying the zinc oxide nano flower suspension micro stirrer for stirring; (c) placing the zinc oxide/indium tin oxide electrode in the quartz tube furnace outlet, heating from room temperature to 900-1100 degrees C with the rate of 10-20 degrees C/minute for 40-60 minutes under the protection of argon gas, incubating at 900-1100 degrees C, heating at 900-1100 degrees C in the tube furnace with methane gas at rate of 10-20sccm and then heating in quartz tube furnace with a cooling rate of 10-20 degrees C/ minute from 900-1100 degrees C, cooling to room temperature to obtain graphene/zinc oxide nano flower suspension/indium tin oxide electrode, where the flow rate of the of argon gas is 450-550sccm.