▎ 摘　　要

NOVELTY - A nanocomposite material preparation method involves preparing zinc oxide nanoparticles followed by obtaining cadmium sulfide, adding graphene oxide to deionized water and ultrasonically reacting for 2 hours to obtain suspension. The zinc oxide nanoparticles and cadmium sulfide are added to the suspension followed by hydrothermally treating for 48 hours, synthesizing sample with water, washing with ethanol for several times, collecting resulting solid by centrifugation and drying at 50 degrees C for 4 hours. USE - Method for preparing nanocomposite material that is utilized for constructing sensor for detecting mercury ions (claimed), where the sensor is an electrochemical DNA sensor. ADVANTAGE - The method enables preparing nanocomposite material with suitability for constructing electrochemical DNA sensor with high sensitivity and high accuracy for detecting mercury ions with better specificity in a rapid manner. DETAILED DESCRIPTION - A nanocomposite material preparation method involves dissolving zinc chloride in deionized water. The obtained solution is heated to 90 degrees C followed by slowly stirring, adding sodium hydroxide drop-by-drop, continuously stirring under heating conditions of 90 degrees C for 1 hour, cooling reactant to room temperature, precipitating and separating. The precipitate is washed several times using deionized water. The precipitate is dispersed in isopropanol followed by ultrasonically reacting for 10 minutes, centrifuging and collecting supernatant. The supernatant is placed in muffle furnace at 350 degrees C for 3 hours, such that preparing zinc oxide nanoparticles followed by dissolving cadmium acetate in deionized water, stirring, adding mercaptoacetic acid and adjusting pH of the solution to 11.5 with sodium hydroxide. The obtained solution is added with sodium sulfide followed by continuously stirring till formation of yellow suspension. The suspension is centrifuged followed by washing the supernatant with deionized water and ethanol (thrice), such that obtaining solid sample. The sample is dried in vacuum oven at 60 degrees C for 2 hours, such that obtaining cadmium sulfide followed by adding graphene oxide to deionized water and ultrasonically reacting for 2 hours to obtain suspension. The zinc oxide nanoparticles and cadmium sulfide are added to the suspension followed by hydrothermally treating for 48 hours, synthesizing sample with water, washing with ethanol for several times, collecting resulting solid by centrifugation and drying at 50 degrees C for 4 hours. An INDEPENDENT CLAIM is also included for a method for constructing sensor for detecting mercury ions.