▎ 摘　　要

NOVELTY - Preparing uricase biosensor based on dicalcium phosphate-reduced graphene/nano gold particles comprises e.g. providing glassy carbon electrode on the suede of the aluminum oxide polishing powder after coarse grinding, taking aluminum oxide polishing powder fine grinding by ultra-pure water to clean, using ultrapure water to clean in the nitric acid/ethanol mixed solution and each ultrasonic washing secondary water, washing in ultra-pure water and drying, glassy carbon electrode pre-processing to obtain the pre-processed glass carbon electrode and taking the obtained working electrode. USE - The method is useful for preparing uricase biosensor based on dicalcium phosphate-reduced graphene/nano gold particles (claimed). ADVANTAGE - The method is simple process and greatly improves enzyme inactivation; has characteristics of high sensitivity, has large linear detection range, low detection limit, good repeatability and simple operation. DETAILED DESCRIPTION - Preparing uricase biosensor based on dicalcium phosphate-reduced graphene/nano gold particles comprises (i) providing glassy carbon electrode by 0.5 mu m on the suede of the aluminum oxide polishing powder after coarse grinding, taking aluminum oxide polishing powder fine grinding by ultra-pure water to clean, using 0.35 mu m, using ultrapure water to clean in the nitric acid/ethanol mixed solution with volume ratio of 1:3 and each ultrasonic washing secondary water for 3-5 minutes, washing in ultra-pure water and drying, glassy carbon electrode pre-processing to obtain the pre-processed glass carbon electrode; (ii) taking the obtained working electrode, and 0.5 mol/l concentration of sulfuric acid (H2SO4) in the solution for cyclic volt-ampere scanning, scanning range is -1 V to 1 V, and scanning rate is 50 mv/s, scanning the section number is 20 section, until the cyclic volt-ampere scanning curve is stable, if the cyclic voltammogram peak potential difference less than 80 mv, performing electrode activation or the electrode at a concentration of 0.2 mol/l potassium nitrate and recording in potassium ferricyanide solution of cyclic voltammetry curve, at scanning speed of 50 mv/s, scanning range is -0.1 V to 0.6 V until become stable, obtaining activated glassy carbon electrode; (iii) adding 0.01% chloroauric acid aqueous solution in 250 ml round flask with a condensing device (100 ml) heating to boil, accurately adding 1% trisodium citrate aqueous solution under vigorously stirring for 0.3-3 ml, chloroauric acid aqueous solution becomes purple from yellow within 1 to 3 min, continuously boiling for 10-20 minutes, cooling, and using distilled water to return to the original volume to obtain the gold sol of the highest absorption peak in the visible light region is 220-525 nm, to obtain AuNPs and GO; (iv) using sodium hydrogen phosphate and calcium chloride, cooling for 1-2 hours, mixing and stirring uniformly at 10-25 degrees C, adding the AuNPs and 3-10 ml GO obtained in step (iii) to adjust the pH to 3-5 and stirring uniformly, continuously cooling in the pre-cooling temperature for 1-2 hours after 100-160 degrees C and carrying out hydrothermal reaction for 10-14 hours, performing suction filtration and drying to obtain DCPA-rGO/AuNPs mixture with uniform morphology; (v) taking the working electrode in step (ii), mixing liquid coated on the glassy carbon electrode surface of an activated DCPA-rGO/AuNPs obtained in the step (iv), drying and dropping by coating and drying and reaches saturation at the working electrode until to obtain the composition material, using ultrapure water to wash and drying, obtaining dicalcium- rGO/AuNPs substrate with film electrode; (vi) taking 5 ml sample tube in turn adding 10 mu m concentration of 2% glutaraldehyde aqueous solution, 50 mu l uricase solution phosphate buffered saline solution with pH of 7 and 5 mg uricase, Nafion (RTM: Perfluorinated resin solution) for constant volume to 500 mu l, mixing, shaking, obtaining polyaniline-uricase mixed solution; and (vii) adding surface of the substrate electrode with the DCPA-rGO/AuNPs membrane obtained in step (v) and adding 20 mu l uricase mixture obtained in step (vi), drying and forming glassy carbon electrode surface formation of uricase membrane.