Preparation Of Ni-based Transition Metal Nanozymes And Intelligent Colorimetric Detection Of Drug Residue

With the rapid development of industry and agriculture in the current society,the pollution of the ecological environment has also shown diversity and complexity,and has seriously endangered human life and health.Therefore,it is of great significance to build a fast detection method to detect and analyze pollutants in the environment.There are many advantages than color detection technology,such as:simple operation,low cost,wide adaptation,etc.Therefore,the development of rapid and efficient than color sensing detection has to attract more and more attention.Nanozyme is a type of nano-material with catalytic activity and has been proven to catalyze the obvious color changes in catalytic substrates under the right conditions for color sensing technology.In this thesis,two kinds of Ni-based transition metal nanoenzymes with peroxidase like activity were synthesized,and a colorimetric intelligent sensing system was further successfully constructed and used for biological detection.The main results are as follows:（1）A simple solvent thermal method is used to prepare a dual-metal organic framework Fe₂Ni-MIL-88B nanomaterial,which shows the activity of the oxide enzyme.The enzyme-type activity of Fe₂Ni-MIL-88B is the addition of Ni elements that change the control environment of Fe₂MO（M=Ni）and phenyl acidic acid,causing electronic transfer between Fe-Ni.When H₂O₂exists,the Fe₂Ni-MIL-88B can catalyze oxidation 3,3’,5,5’-tetramethyl benzidine（TMB）to form a blue oxidation product ox-TMB.When antibiotics such as doxycycline hydrochloride（DOX）and metacycline hydrochloride（MET）are present,they can prevent the catalytic oxidation of TMB.This principle can be used to detect DOX and MET,and an intelligent sensing platform for detecting DOX and MET is further established in combination with smart phone APP.In addition,Fe₂Ni MIL-88B exhibits excellent antibacterial activity against Gram negative bacteria and can be used as an antibacterial agent.This study provides a multifunctional detection platform for DOX and MET in drug residue monitoring,and also has certain application prospects in the field of antibiotics.（2）Sr Co Ni O₃nanoenzyme was synthesized by calcination at high temperature.The incorporation of Ni leads to the conversion of Co³⁺to Co²⁺in Sr Co Ni O₃,and promotes the conversion of Co²⁺to Co³⁺and Sr²⁺to Sr⁰after the reaction.Therefore,the addition of Ni is the key driving factor of charge redistribution and chemical bond coupling.The nano enzyme has peroxidase activity and can catalyze the oxidation of TMB to oxidized TMB（ox-TMB）under the condition of adding oxidant H₂O₂.Dopamine hydrochloride（DAH）can successfully block the production of cationic free radicals and restore them to the original colorless TMB molecules.When Cd²⁺is added to it,it can turn into blue ox-TMB.Based on the above experimental phenomena,an"on-off-on"colorimetric sensing system was developed and designed for DAH and Cd²⁺detection.An intelligent sensor system for detecting DAH and Cd²⁺is built by combining smart phones.