▎ 摘　　要

NOVELTY - Preparation of nano-copper/cuprous oxide/graphene-based composite material involves dispersing 0.05-0.2 g graphene oxide in 20-50 mL deionized water, adjusting pH of obtained graphene oxide solution to 5-11 with an aqueous ammonia solution, then ultrasonically processing for 0.5-2 hours, adding 5-20 mL 0.5-1 mol/L copper sulfate solution to the processed graphene oxide solution, ultrasonically processing for 20-60 minutes, adding 7-20 mL 1.5 mol/L ascorbic acid solution, heating obtained mixed solution at 40-100 degrees C for 4-24 hours in a water bath, washing the reaction product, and drying. USE - Preparation of nano-copper/cuprous oxide/graphene-based composite material used for preparing nano-copper/cuprous oxide/graphene-based composite material-modified glassy carbon electrode used in electrochemical sensor for detecting ascorbic acid content (all claimed). ADVANTAGE - The electrochemical sensor containing the nano-copper/cuprous oxide/graphene-based composite material-modified glassy carbon electrode, has excellent electrocatalytic activity for ascorbic acid, low detection limit, wide linear range, and anti-interference performance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (i)preparation of a nano-copper/cuprous oxide/graphene-based composite material-modified glassy carbon electrode, which involves adding 5-20 mg nano-copper/cuprous oxide/graphene-based composite material and 50-150 mu L 0.5% Nafion (RTM: sulfonated tetrafluoroethylene-based fluoropolymer-copolymer) solution to 2-10 mL azodicarbonamide solvent, ultrasonically processing, obtaining uniformly mixed suspension, polishing a glassy carbon electrode using alumina polishing powder, ultrasonically cleaning the electrode using deionized water and absolute ethanol, respectively, dropping 3-10 mu L mixed suspension onto the polished glassy carbon electrode surface, and drying; #(ii) electrochemical sensor, which comprises the nano-copper/cuprous oxide/graphene-based composite material-modified glassy carbon electrode; and #(iii) detection of ascorbic acid content, which involves preparing to-be-tested sample solution, determining oxidation current value of ascorbic acid in the to-be-tested sample solution using the electrochemical sensor, by differential pulse voltammetry, and converting the concentration of ascorbic acid based on the linear equation: Ipa = 8.698c+4.737(R2), where R2 is 0.997, c is the concentration of ascorbic acid in mu mol/L, and Ipa is the peak oxidation current value obtained by pulse voltammetry in mu A.