Optical Detection Of Glucose And Aflatoxin With Metal-organic Frameworks Composite Material

Food quality and safety monitoring is an indispensable part of ensuring human health.Faced with a large number of test samples,the difficulty of monitoring is greatly increased.Therefore,there is an urgent need to develop new methods that can be used to efficiently,quickly and sensitively detect various components in food,and it has become one of the research focuses of the majority of scientific researchers.The optical method is widely used in various detection methods due to its fast response speed,low interference,simple design and easy operation.Due to the specific catalytic properties of natural enzymes,most of these methods use natural enzymes.Natural enzymes have disadvantages such as difficulty in purification,high price,poor stability,and low temperature storage,which limit the promotion of these methods.The metal-organic framework of emerging materials has been applied in improving the stability of enzymes and simulating natural enzymes.Therefore,this article is based on the metal-organic framework materials combined with optical analysis methods for rapid detection of glucose and aflatoxin B1 in food.The experiment is divided into the following two parts:1.In this work,a high-stability detection method for glucose in food is established.Firstly,glucose oxidase and carbon dots are co-encapsulated in the zeolite-like imidazole ester framework material at room temperature to form a nanocomposite as a fluorescent probe for detecting glucose.Under neutral conditions,the composite material can efficiently catalyze the oxidation of glucose to generate H₂O₂.The Fenton-like reaction between H₂O₂and Co²⁺generates free radicals(·OH),which quenches the fluorescence of carbon dots,thereby detecting glucose.The detection limit of the constructed fluorescent probe under the optimal conditions is 0.16?M,and the recovery rate is 106.8%?110.7%.In this experiment,the metal-organic framework nanocomposite material embedded by glucose oxidase and carbon dots was synthesized at room temperature,and is successfully used for glucose detection in actual samples,and the composite material has high stability at room temperature.2.In this work,a new method of immunoassay is constructed.The antibody modified MOFs material with mimic enzyme activity is used as a colorimetric probe,and the magnetic nanomaterial combines with the antigen to form a competitive and easy-to-separate immunoprobe.As a kind of Cu-MOFs,HKUST-1 shows great mimetic enzyme activity,mild synthesis conditions,high stability,and rich functional groups on the surface that are easy to modify.GOx@HKUST-1 was synthesized by simple mixing at room temperature,and then modified by antibody to form a complex(HKUST-1-antibody-AFB1).AFB1 competes anti-GOx@HKUST-1 with the magnetic immunoprobe modified by antigen(Fe₃O₄-BSA-AFB1).When the AFB1 in the system is not enough to be completely blocked HKUST-1-antibody-AFB1,Fe₃O₄-BSA-AFB1 will bind to it.After magnetic separation,the colorimetric determination is carried out.If the composite material contains colorimetric probes,it can efficiently catalyze the production of H₂O₂ from glucose.In the presence of HKUST-1peroxidase,H₂O₂ is used as an intermediate product and immediately converted to·OH.It will oxidize TMB,and the absorbance is observed using ultraviolet-visible absorption spectroscopy at 652 nm.There was a linear correlation between AFB1 concentration and absorbance in the range of 0.01-0.1 ng/mL,and the detection limit was 0.004 ng/mL.The material has great selectivity and stability,and can be used for the detection of corn samples.