▎ 摘　　要

NOVELTY - A graphene/titanium dioxide/platinum-palladium nano composite material-based cholesterol biosensor preparing method involves preparing graphene/titanium dioxide nano composite material. The composite material is dispersed in diethylene glycol diacrylate phthalate aqueous solution to obtain nano dispersion. The nano dispersion is added to glassy carbon electrode and immobilized with cholesterol oxidase solution to obtain cholesterol modified electrode, followed by placing cholesterol-modified electrode, reference electrode and counter electrode in electrolyte to obtain the finished product. USE - Method for preparing graphene/titanium dioxide/platinum-palladium nano composite material-based cholesterol biosensor for quantitative detection of cholesterol in food (claimed). ADVANTAGE - The method enables preparing cholesterol biosensor with improved specific surface area, faster electronic transfer, excellent response ability, high sensitivity, good repeatability, stable performance, good selectivity, excellent catalytic performance, good application prospect and good bioactivity. DETAILED DESCRIPTION - A graphene/titanium dioxide/platinum-palladium nano composite material-based cholesterol biosensor preparing method involves preparing graphene/titanium dioxide nano composite material by mixing 50-60 mg graphene and 2.5-3 mL sodium dodecylbenzenesulfonate solution, diluting to 10-15 mL, ultrasonically dispersing for 15-30 minutes, adding 20-25 mL titanium trichloride and 2.5-3 mL hydrogen peroxide solution under stirring, adjusting the volume to 80 mL with distilled water, stirring at 90-95 degrees C for 16-18 hours, centrifuging, washing with ethanol and water, drying in a vacuum oven at 70-80 degrees C for 10-12 hours and calcining at 400 degrees C for 2 hours to obtain graphene/titanium dioxide nano composite material. The graphene/titanium dioxide nano composite material is ultrasonically dispersed in diethylene glycol diacrylate phthalate aqueous solution to obtain graphene/titanium dioxide nano dispersion. The graphene/titanium dioxide nano dispersion is added to glassy carbon electrode after polishing treatment, electrodeposited on modified electrode and immobilized with cholesterol oxidase solution to obtain cholesterol modified electrode, followed by placing cholesterol-modified electrode, reference electrode and counter electrode in an electrolytic solution to obtain the finished product, and testing cholesterol content of the food using the cholesterol biosensor.