▎ 摘　　要

NOVELTY - Preparing biosensor for detecting pancreatic cancer marker e.g. cancer antigen (CA)19-9, involves (a) adding graphite and potassium permanganate to flask, adding sulfuric acid and phosphoric acid, hearing mixture, and obtaining graphene oxide, (b) dissolving graphene oxide in cetyltrimethyl ammonium bromide, adding nitric acid solution, stirring added materials, adding polypyrrole, and obtaining polypyrrole/graphene oxide, and (c) calcining polypyrrole/graphene oxide, adding sodium hydroxide solution, centrifuging mixture, washing pellet, and drying product. USE - The method is useful for preparing biosensor for detecting pancreatic cancer marker e.g. cancer antigen (CA)19-9 (claimed) used in diagnosis and treatment of tumor. DETAILED DESCRIPTION - Method for preparing biosensor for detecting pancreatic cancer marker e.g. cancer antigen (CA)19-9, involves (a) adding 0.3-0.6 g graphite and 1.8-3.6 g potassium permanganate to 500 ml flask, then adding 36-72 ml sulfuric acid and 4-8 ml phosphoric acid to the flask, hearing mixture at 50 degrees C for 12 hours, pouring 40-80 ml cold water to the mixture, further adding 0.6-2 ml hydrogen peroxide, stirring mixture for 30 minutes, performing centrifugation, adding hydrochloric acid/ethanol solution, collecting precipitate, washing the precipitate with ether, and drying washed precipitate at 40 degrees C under vacuum condition to obtain graphene oxide, (b) dissolving 5-10 g graphene oxide in 80 ml cetyltrimethyl ammonium bromide, adding 1 mol/l nitric acid solution, stirring added materials, heating mixture to 100 degrees C, further adding 0.2-1 g polypyrrole, continuously heating mixture for 60 minutes, then adding 1-3 g ammonium persulfate, reacting mixture for 180 minutes, centrifuging mixture, washing pellet, drying the pellet at 40 degrees C under vacuum to obtain polypyrrole/graphene oxide, and (c) calcining polypyrrole/graphene oxide at 800 degrees C for 2 hours under argon pressure to obtain carbon nitride/graphene, then adding 2-10 mg carbon nitride/graphene and 3 mg/ml potassium tetrachloroplatinate, performing reaction for 0.5 hours, adding 20 mol/l sodium hydroxide solution, performing reaction under power of 300 W for 110 seconds, centrifuging mixture, washing pellet, and drying product at 60 degrees C under vacuum condition. An INDEPENDENT CLAIM is included for method for detecting pancreatic cancer marker e.g. CA19-9.