▎ 摘　　要

NOVELTY - Method, comprises (i) polishing a glassy carbon electrode with a diameter of 4 mm with aluminum oxide polishing powder, cleaning with ultrapure water, dropping nitrogen-graphene quantum dots (N-GQDs) doped isoreticular metal organic framework-3 (IRMOF)-3N-GQDs solution onto the electrode surface, and drying, (ii) dropping procalcitonin primary antibody Ab1, washing with PBS buffer, and drying, (iii) continuously dropping bovine serum albumin solution onto the electrode surface, washing with PBS buffer, and drying at room temperature, (iv) dropping series of different concentrations of procalcitonin antigen to the electrode surface, incubating, washing with PBS buffer, and dry at room temperature, and (v) adding gold-modified zinc oxide nanorods to the electrode surface, combining with the secondary antibody marker zinc oxide (ZnO) doped gold-antibody 2 (Ab2) solution of the procalcitonin recognition antibody, washing with PBS buffer, and drying. USE - The method is useful for preparing electrochemical immune sensor based on isoreticular metal organic framework-3 internal and external load nitrogen doped quantum dot composite material. ADVANTAGE - The method: utilizes nitrogen-doped quantum dot, which has higher quantum yield and more active sites compared with the graphene quantum dot; synthesizes IRMOF-3, which has large specific surface area, good pore regularity and adjustable aperture, can load nitrogen doped quantum dot with high quantity, improves the load amount of the luminescent material and provides a continuously stable strong electrochemical light emitting signal; constructs sandwich quenching type electrochemical immune sensor; and acheives ultra-sensitive detection of procalcitonin (with a detection limit of 12.58 femtogram/ml).