▎ 摘　　要

NOVELTY - A copper detecting method involves pre-processing a substrate sequentially deposited require activation, washing, drying, preparing a graphene oxide deposition solution, dissolving a graphene oxide powder in a phosphate buffer solution, performing electrochemical reduction and deposition of graphene oxide using cyclic voltammetry to reduce graphene oxide, depositing the graphene oxide deposition solution on the substrate, stirring during the deposition process, immersing electrochemical detection device in an acidic test solution containing heavy metal ions, applying a deposition potential for pretreatment, stirring the solution to be tested during the pretreatment process, after the stirring is stopped, performing scanning by differential pulse stripping voltammetry, after scanning, and recording the peak potential and current value of copper to realize the detection of copper. USE - Method for detecting copper using nano-gold-graphene composite electrode. ADVANTAGE - The method enables detecting copper with high sensitivity, low detection limit, better detection effect, strong conductivity, large specific surface area, better electro-catalysis property, and promotes electron transfer between the electroactive substance and the electrode. DETAILED DESCRIPTION - A copper detecting method involves pre-processing a substrate sequentially deposited require activation, washing, drying, preparing a graphene oxide deposition solution, dissolving a graphene oxide powder in a phosphate buffer solution, ultrasonic peeling, taking out, shaking up and down to mix evenly to form a graphene oxide colloidal dispersion of 1-2 mg/mL, performing electrochemical reduction and deposition of graphene oxide using cyclic voltammetry to reduce graphene oxide, depositing the graphene oxide deposition solution on the substrate, stirring during the deposition process, and performing a set of potential cycles at a scanning rate of 25 mV/s in the range of -1.50-0.60 V, after electrodeposition, washing and drying the obtained graphene oxide-modified electrode to obtain a matrix covering the reduced graphene oxide, preparing a mixed solution of chloroauric acid and sulfuric acid, when the mixed solution has a concentration of chloroauric acid of 5-10 mmol/L and a concentration of sulfuric acid of 0.5-1 mol/L, and electrochemically depositing nano-gold and placing the substrate in a mixed solution of chloroauric acid and sulfuric acid, performing electrochemical deposition of nano-gold by potentiostatic method with a deposition potential of 0.01 V and a deposition time of 120 seconds to obtain a nano-gold-graphene composite electrode, washing and drying the composite electrode, performing electrochemical analysis and detection of copper in the test solution, immersing electrochemical detection device in an acidic test solution containing heavy metal ions, when the pH of the acidic test solution is 3.6-5.4, the working electrode is the nano-gold-graphene composite electrode, the reference electrode is silver/silver chloride, and the counter electrode is platinum wire, applying a deposition potential for pretreatment, when the deposition potential is -1.5-0V, and the deposition time is 120-200 seconds, stirring the solution to be tested during the pretreatment process, when the stirring speed is 400-800 rpm, after the stirring is stopped, performing scanning by differential pulse stripping voltammetry, when the scanning potential is -1.4-0V, after scanning, and recording the peak potential and current value of copper to realize the detection of copper.