▎ 摘　　要

NOVELTY - Preparing pentaethylene hexamine functional graphene quantum dot (PEHA-GQD)/rare earth up-conversion composite comprises e.g. (i) dissolving citric acid and pentaethylene hexaamine with molar ratio of 1:0.01-1:1 in ultrapure water to obtain mixed solution, heating the mixed solution at 150-200 degrees C for 1-8 hours for adjusting the pH to 6.8-7.2, dialyzing for 12-60 hours and removing substances with molecular weight below 3kD, freeze-drying the solution collected after dialysis to obtain solid pentaethylene hexaamine functionalized graphene quantum dot PEHA-GQD, and dispersing solid PEHA-GQD in ultrapure water to obtain PEHA-GQD dispersion, (ii) preparing rare earth up-conversion nanocrystals, coating PVP on the surface of the rare earth nanocrystals to obtain PVP-coated rare earth up-conversion nanocrystals, and(iii) dispersing the PVP-coated rare earth upconversion nanocrystals obtained in the step (ii) in ultrapure water. USE - The composite and sensor are useful in detecting the content of malathion (claimed). ADVANTAGE - The method: realizes the quantitative determination of organophosphorus pesticides; and simple and easy to popularize. DETAILED DESCRIPTION - Pentaethylene hexamine functional graphene quantum dot (PEHA-GQD)/rare earth up-conversion composite comprises (i) dissolving citric acid and pentaethylene hexaamine with molar ratio of 1:0.01-1:1 in ultrapure water to obtain mixed solution, heating the mixed solution at 150-200 degrees C for 1-8 hours for adjusting the pH to 6.8-7.2, dialyzing for 12-60 hours and removing substances with molecular weight below 3kD, freeze-drying the solution collected after dialysis to obtain solid pentaethylene hexaamine functionalized graphene quantum dot PEHA-GQD, and dispersing solid PEHA-GQD in ultrapure water to obtain PEHA-GQD dispersion, (ii) preparing rare earth up-conversion nanocrystals, coating PVP on the surface of the rare earth nanocrystals to obtain PVP-coated rare earth up-conversion nanocrystals, where the rare earth up-conversion nanocrystals are sodium gadolinium fluoride (NaGdF4), ytterbium, erbium, NaGdF4:ytterbium, erbium-NaGdF4, sodium yttrium fluoride (NaYF4): ytterbium, erbium-NaYF4 or NaYF4: ytterbium, and erbium, and(iii) dispersing the PVP-coated rare earth upconversion nanocrystals obtained in the step (ii) in ultrapure water, adding 0.1-25 mg/ml PEHA-GQD dispersion obtained in the step (i), stirring at 15-30 degrees C for 0.1-12 hours, centrifuging, and washing to obtain PEHA-GQD/rare earth up-conversion complex. INDEPENDENT CLAIM are also included for: (1) bioluminescence sensor based on the PEHA-GQD/rare earth up-conversion complex, comprising (i) adding EDC and NHS to the ligated DNA LDNA solution, incubating at 30-40 degrees C for 1-3 hours and activating the terminal carboxyl group on the LDNA, adding the dispersion liquid by dispersing the PEHA-GQD/rare earth up-conversion complex in ultrapure water, and shaking at 3-5 degrees C for 8-12 hours, centrifuging and removing excess LDNA to obtain LDNA-terminated PEHA-GQD/rare earth upconversion complex dispersion, and(ii) mixing the same amount of aptamer AS solution and auxiliary chain AP solution, incubating, adding the sample to be tested, and incubating at 35-39 degrees C for 1-3 hours, adding carboxytetramethylrhodamine modified hairpin TMR-H1 Hairpin H2 and Cutsmart buffer, incubating at 35-39 degrees C for 30-60 minutes, adding Nt.AlwI solution, incubating at 35-39 degrees C for 1-2 hours and then inactivating the enzyme, adding the dispersion of the LDNA-terminated PEHA-GQD/rare earth upconversion complex obtained in the step (i), mixing and shaking complementary strand CS solution, and incubating at 35-39 degrees C for 60-150 minutes to obtain bioluminescence sensor; and (2) use of sensor in detecting the content of malathion, comprising taking the up-conversion fluorescence intensity of the bioluminescence sensor at 541 nm with different concentrations of malathion standard solution as a parameter, and establishing linear model with the logarithmic value of the concentration to obtain standard curve, measuring the up-conversion fluorescence intensity of the sensor system with the sample to be tested with malathion, and substituting into the standard curve to obtain the content of malathion.