▎ 摘　　要

NOVELTY - Preparing electrochemical biosensor based on gold-palladium-graphene quantum dot composite material comprises (i) taking citric acid and aspartic acid in a molar ratio of 1:1 and uniformly mixing, adding deionized water and ultrasonically dissolving to obtain a reaction solution, placing the reaction solution in an baking oven, reacting at an oven temperature of 150-250 degrees C for 0.5-10 hours to obtain a solid product of aspartic acid quantum dots, and preparing the solid product of aspartic acid quantum dots into an aqueous solution of 25-200 mg/ml, and (ii) mixing 5-50 ml of 0.1-0.5 mg/ml chloroauric acid solution and 1-5 ml of 1-10 mg/ml tannic acid solution, adding 0.1-2 ml aspartic acid quantum dot aqueous solution obtained in the step (i). USE - The method is useful for preparing electrochemical biosensor based on gold-palladium-graphene quantum dot composite material. ADVANTAGE - The composite material has high electrocatalytic activity, high sensitivity, stability, usability, and high specificity detection. DETAILED DESCRIPTION - Preparing electrochemical biosensor based on gold-palladium-graphene quantum dot composite material comprises (i) taking citric acid and aspartic acid in a molar ratio of 1:1 and uniformly mixing, adding deionized water and ultrasonically dissolving to obtain a reaction solution, placing the reaction solution in an baking oven, reacting at an oven temperature of 150-250 degrees C for 0.5-10 hours to obtain a solid product of aspartic acid quantum dots, and preparing the solid product of aspartic acid quantum dots into an aqueous solution of 25-200 mg/ml, (ii) mixing 5-50 ml of 0.1-0.5 mg/ml chloroauric acid solution and 1-5 ml of 1-10 mg/ml tannic acid solution, adding 0.1-2 ml aspartic acid quantum dot aqueous solution obtained in the step (i), heating at 40-100 degrees C until the color of the solution becomes dark red, maintaining the temperature for 3-10 minutes, and then cooling to ambient temperature to prepare a gold seed solution, (iii) dispersing 5-100 mu l aspartic acid quantum dot aqueous solution, and chloroauric acid and palladium(II) chloride solution in a volume ratio of 1:1 obtained in the step (i) in another container, where the chloroauric acid and palladium(II) chloride solutions are both 0.5-5 ml, and the concentration is 25-200 mg/ml, then adding 1-20 ml ultrapure water, incubating for 2-10 minutes, adding 0.1-0.5 ml silver nitrate solution with concentration of 2-15 mM, 10-80 mu l of the gold seed solution obtained in the step (ii), and 5-20 ml 30% hydrogen peroxide solution to obtain a mixed solution A, after the color of the mixed solution A turns blue, continuously stirring for 10-80 seconds, then centrifuging at 5000-10000 revolutions per minute (rpm) for 5-15 minutes to collect the aspartic acid-functionalized graphene quantum dot-gold-palladium hybrid, washing the collected aspartic acid-functionalized graphene quantum dot-gold-palladium hybrid using ultrapure water for 2-5 times, and then dispersing in 0.5-2 ml tris-hydrochloride buffer solution with pH of 6-8, (iv) dispersing 1-8 mg graphene aerogel in 2-20 ml ultrapure water and mixing with 0.5-5% chitosan solution in a volume ratio of 40:1-10:1 to obtain mixed solution B, taking 3-10 mu l of the mixed solution B on the surface of the pre-treated glassy carbon electrode, and then drying it in nitrogen to obtain a graphene aerogel-glassy carbon electrode sensor. INDEPENDENT CLAIMS are also included for: (1) use method of electrochemical biosensor based on gold-palladium-graphene quantum dot composite material for detecting acetamiprid, comprising dropping 5 mu l acetamiprid solution to the surface of the aptamer sensor, after incubating for 1 hour, washing using phosphate buffered saline, drying with nitrogen, soaking in 10 mM phosphoric acid buffered saline having pH of 7.4, measuring by differential pulse voltammetry, where the parameters are set to a scan rate of 4 mV/second, pulse amplitude of 50 mV, pulse width of 20 ms, and initial potential of -0.2 V, and recording the differential pulse voltammetry curve between -0.3-0.5 V. The electrochemical biosensor based on the gold-palladium-graphene quantum dot composite is an aptamer sensor made of aspartic acid-functionalized graphene quantum dot-gold-palladium hybrid; and (2) use method of electrochemical biosensor based on gold-palladium-graphene quantum dot composite material for combining toxicity evaluation of binary organic phosphorus pesticides at the cellular level, comprising taking the treated human liver cancer cells that have grown to the logarithmic phase, adding mixed solution of chlorpyrifos and acetamiprid prepared in a concentration ratio of 1:1, diluting chlorpyrifos and acetamiprid with acetone before use and then adding to the cell culture medium to prepare the volume concentration of acetone below 0.5%, using the cell base containing 0.5% volume concentration of acetone as the experimental control group, continuously polishing the glass carbon electrode on the polishing cloth with 0.3 mu m and 0.05 mu m alumina slurry, completely washing using distilled water, then ultrasonically treating in ethanol and distilled water for 10 minutes, dropping 5 mu l graphene aerogel solution, after drying the electrode, dropping 5 mu l aspartic acid-functionalized graphene quantum dot-gold-palladium hybrid dispersion, soaking the modified glassy carbon electrode in 5 mM folic acid with a mixture of 0.1 M NN-hydroxysuccinimide and 0.4 M ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride at room temperature for 4 hour, washing using deionized water to obtain folic acid/gold palladium-graphene quantum dots/graphene aerogels/glassy carbon electrodes, dropping 10 mu l human liver cancer cell suspension having concentration of 5x 105 cells/ml to the surface of folic acid/gold palladium-graphene quantum dots/graphene aerogels/glassy carbon electrodes, incubating at 37 degrees C for 8 hours, soaking in phosphoric acid buffered saline solution to remove uncaught cells before to electrochemical measurements, and cycling modified electrode DPV between -0.2-0.6 V for many times until a reproducible response is obtained. The electrochemical biosensor based on the gold-palladium-graphene quantum dot composite material is an aptamer sensor made of aspartic acid-functionalized graphene quantum dot-gold-palladium hybrid.