▎ 摘　　要

NOVELTY - The preparation method of heavy metal ion electrochemical sensor, involves: putting the carbon nano-tube in concentrated sulfuric acid-concentrated nitric acid mixed solution, ultrasonically processing for 2-6 hours at 20-80 °C, adding deionized water centrifugal washing until the washing liquid is neutral, solid freezing and drying to obtain the carboxylated carbon nano-tube; putting the carboxylated carbon nano-tube and the graphene in the deionized water, ultrasonically dispersing for 1-3 hours, centrifuging at 6000-15000 revolutions per minute, removing the supernatant deionized water washing the precipitate, freezing and drying to obtain the carboxylated carbon nano tube/graphene composite material; adding the carboxylated carbon nano-tube/graphene composite material into ethanol solution to ultrasonically treat for 15-60 minutes to obtain 0.5-3 mg/mL carboxylation carbon nano-tube/ graphene suspension liquid. USE - Preparation method of heavy metal ion electrochemical sensor. ADVANTAGE - The electrochemical sensor is based on a high-performance carboxylated carbon nanotube/graphene composite material, which is applied to the working electrode of a traditional three-electrode system and a composite electrode system. Surface modification, and the electrochemical detection of the sensor in cadmium and lead ion solutions with an ultra-wide concentration range is realized by dynamically optimizing deposition/enrichment time and mercury/bismuth ion concentration. The experiment result shows that the method can realize synchronous detection of cadmium and lead ion in water solution under the three different operating parameters. A very wide linear detection range is obtained. The modified material of electrochemical sensor working electrode has the advantages of easy industrial production strong electrochemical performance. The operation strategy of the electrochemical sensor has dynamic optimization capability so that the electrochemical sensor has a linear detection range better than the market absolute product. DETAILED DESCRIPTION - The preparation method of heavy metal ion electrochemical sensor, involves: putting the carbon nano-tube in concentrated sulfuric acid-concentrated nitric acid mixed solution, ultrasonically processing for 2-6 hours at 20-80 °C, adding deionized water centrifugal washing until the washing liquid is neutral, solid freezing and drying to obtain the carboxylated carbon nano-tube; putting the carboxylated carbon nano-tube and the graphene in the deionized water, ultrasonically dispersing for 1-3 hours, centrifuging at 6000-15000 revolutions per minute, removing the supernatant deionized water washing the precipitate, freezing and drying to obtain the carboxylated carbon nano tube/graphene composite material; adding the carboxylated carbon nano-tube/graphene composite material into ethanol solution to ultrasonically treat for 15-60 minutes to obtain 0.5-3 mg/mL carboxylation carbon nano-tube/ graphene suspension liquid, coating the carboxylated carbon nanotube/graphene suspending liquid on the working electrode, after drying, dropping Nafion (RTM: Sulfonated tetrafluoroethylene) dispersion with concentration of 0.1-20 % on the surface of the working electrode, drying and depositing to obtain the electrochemical sensor modified by Nafion (RTM: Sulfonated tetrafluoroethylene)/carboxylated carbon nanotube/graphene composite material. An INDEPENDENT CLAIM is included for the application of heavy metal ion electrochemical sensor in electrochemical detection of heavy metal ion in water.