▎ 摘　　要

NOVELTY - A chitosan-graphene quantum dot nanocomposite-modified electrode preparing method involves weighing citric acid, and grinding into white powder. The powder is heated to obtain solid sample. The sample is mixed with ultrapure water, and carried out with ultrasonic treatment. The resultant solution is filtered at room temperature to obtain yellow transparent solution, followed by preparing chitosan-graphene quantum point nano composite material, freezing, drying, dispersing material in water, coated the material on surface of a glassy carbon electrode, and drying to obtain a finished product. USE - Method for preparing chitosan-graphene quantum dot nanocomposite-modified electrode that is utilized for detecting heavy metal ions such as zinc, cadmium and lead. ADVANTAGE - The method enables preparing chitosan-graphene quantum dot nanocomposite-modified electrode with high detection sensitivity in a simple, easy and environmental-effective manner. DETAILED DESCRIPTION - A chitosan-graphene quantum dot nanocomposite-modified electrode preparing method involves weighing citric acid, grinding into white powder, and adding the powder in a crucible. The powder is heated using program-controlled cabinet-type electric furnace to obtain solid sample. The sample is mixed with ultrapure water, and carried out with ultrasonic treatment. The resultant solution is filtered at room temperature to obtain yellow transparent solution. The solution is mixed with chitosan powder. The mixture is dissolved in 0.1M acetic acid solution, and stirred. The mixture is added with graphene quantum point solution, and stirred and immersed in sodium hydroxide solution to certain pH value. The solution separated from yellow solid precipitate to obtain chitosan-graphene quantum point nano composite material. The material is freeze and dried for 24 hours. The composite material is ultrasonic dispersed in ultrapure water. The material is coated on surface of a glassy carbon electrode, and dried at room temperature for 1 hour to obtain a finished product.