▎ 摘　　要

NOVELTY - Preparing metal organic framework (MOF) modified magnetic graphene composite material involves dispersing the 400-600 mg graphite in 50-70 mL concentrated nitric acid, refluxing for 6-10 hours in water bath at a temperature of 50-70 degrees C. The product obtained is centrifuged, separated, washed with deionized water until the solution is neutral and dried at 40-60 degrees C to obtain the acidified graphene. The 400-500 mg ferric chloride hexahydrate is dissolved in 40-60 mL ethylene glycol, stirred to obtain yellow transparent solution. USE - Method for preparing metal organic framework modified magnetic graphene composite material used for identifying human serum sample (claimed). ADVANTAGE - The method enables to prepare metal organic framework modified magnetic graphene composite material in cost-effective manner, that has strong hydrophilicity, large specific surface area, stable biocompatibility, high reaction efficiency, low non-specific adsorption, highly efficient separation and enrichment of mixed peptides and great application prospect. DETAILED DESCRIPTION - Preparing metal organic framework (MOF) modified magnetic graphene composite material involves dispersing the 400-600 mg graphite in 50-70 mL concentrated nitric acid, refluxing for 6-10 hours in water bath at a temperature of 50-70 degrees C. The product obtained is centrifuged, separated, washed with deionized water until the solution is neutral and dried at 40-60 degrees C to obtain the acidified graphene. The 400-500 mg ferric chloride hexahydrate is dissolved in 40-60 mL ethylene glycol, stirred to obtain yellow transparent solution. The acidified graphene is dispersed in yellow transparent solution, subjected to ultrasonic treatment for 1.0-2.0 hours, where the ratio of acidified graphene and yellow transparent solution is 150-200 mg:40-60 mL. The ultrasonically treated product, under ultrasonic stirring, is added with trisodium citrate, sodium acetate and polyethylene glycol 20,000 and fully stirred for 1.0-1.5 hours to obtain the mixed solution, which is heated in hydrothermal reaction kettle for 8-10 hours at 180-220 degrees C, cooled to room temperature, magnetically separated, orderly washed with de-ionized water and absolute ethyl alcohol to remove excess raw material and dried at 40-60 degrees C to obtain magnetic graphite material (magG), where the weight ratio of trisodium citrate, sodium acetate and polyethylene glycol 20,000 is 150-180 mg:1.5-2.0 g:1.0-1.5 g. The magG obtained is modified with metal organic framework material with metal ion M as the center to obtain the product, which is denoted as MG@M-MOF. An INDEPENDENT CLAIM is included for method for use of MOF modified magnetic graphene composite material, which involves: (A) mixing MG@M-MOF with target glycosylated peptide solution; (B) uniformly dispersing in 85-95 wt.% acetonitrile/1.0-1.5% trifluoroacetic acid buffer solution at 37-39 degrees C in an enzymolysis tank; (C) centrifuging, separating the composite material and washing 3-5 times with 85-95 wt.% acetonitrile/1.0-1.5% trifluoroacetic acid buffer solution; (D) eluting with 25-30 % acetonitrile/0.10-0.15% trifluoroacetic acid and placing 0.8-1.2 micro-liter eluate on the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) target plate and then drying naturally: (E) dropping 15-25 mg/mL 2,5-dihydroxybenzoic acid of 0.8-1.2 micro-liter concentration to the analyte droplets; and (F) forming a thin layer matrix, drying and carrying out mass spectrometry.