▎ 摘　　要

NOVELTY - A three-dimensional graphene-based levodopa biosensor is prepared by taking nickel(II) chloride hexahydrate, mixing with deionized water, heating, adding hydrazine hydrate, heating, stirring, washing with deionized water, adjusting temperature, adding sodium hydroxide, reacting, obtaining black precipitate, washing with deionized water and ethanol, filtering, drying to obtain nickel nanoparticle, loading into ceramic plate, sintering under argon gas and hydrogen gas, introducing methane gas, cooling to room temperature, coating with multilayer graphene, pumping argon gas and hydrogen gas, dissolving polymethyl methacrylate in ethyl lactate, heating, stirring, adding into prepared raw material, heating, soaking into hydrochloric acid solution and acetone, washing with deionized water, loading into indium tin oxide glass, and freeze drying. USE - Method for preparing three-dimensional graphene-based levodopa biosensor as working electrode in electrochemical biosensor to detect levodopa (claimed). ADVANTAGE - The product has small aperture size, large specific surface area and good conductivity, and has high sensitivity and good selectivity. DETAILED DESCRIPTION - A three-dimensional graphene-based levodopa biosensor is prepared by taking 0.1-0.3 mol nickel(II) chloride hexahydrate, mixing with deionized water, heating at 50 degrees C, adding 0.4-1.2 mol of 80 wt.% hydrazine hydrate, heating at 60 degrees C, stirring at rate of 300-500 revolutions/minute, washing with deionized water, adjusting temperature to 50 degrees C, adding 0.4-1.2 mol of 50 wt.% sodium hydroxide, reacting for 3 hours, obtaining black precipitate, washing with deionized water and ethanol, filtering, drying at 60-80 degrees C for 3-4 hours to obtain nickel nanoparticle, loading into ceramic plate, sintering at 700-800 degrees C at rate of 10-20 degrees C/minute under argon gas and hydrogen gas atmosphere for 30-60 minutes, introducing methane gas at flow rate of 5-20 sccm for 10-20 minutes, cooling to room temperature at cooling rate of 100-150 degrees C/minute, coating with multilayer graphene, pumping argon gas at flow speed of 450-500 sccm and hydrogen gas at flow rate of 100-200 sccm, dissolving 4-5 wt.% polymethyl methacrylate in ethyl lactate, heating at 80-120 degrees C, stirring for 1-2 hours, adding into prepared raw material, heating at 150-200 degrees C for 0.5-1 hour, soaking in 3-4 mol/L hydrochloric acid solution at 80-90 degrees C for 6-12 hours, soaking in acetone at 60-70 degrees C for 4-6 hours, washing with deionized water, loading into indium tin oxide glass, and freeze drying for 0.5-1 hour.