Preparation And Application Of Tannic Acid-metal Complex Film

Tannic acid is a polyphenol widely present in plants.The o-phenol structure of tannic acid can be chelated with metal ions to form tannic acid-metal complexes film on any substrate.The preparation of tannic acid-metal complex film has the characteristics of simple,rapid,mild conditions,and reversible response to external stimuli.Because of the better biocompatibility of tannic acid-metal complex film,its application in many fields has also been increasingly valued by researchers.In this thesis,we mainly studied the tannic acid-metal complex films in biosensing,adsorption and catalytic reduction of organic dyes.The specific research content as follows:?1?Using the rapid reaction of tannic acid with Fe³⁺and its generates a dense complex on the glassy carbon electrode,so it can immobilize the HRP on the electrode,and a biosensor for H₂O₂sensing was constructed.The sensor has good reproducibility and has a low detection limit.The detection range for H₂O₂ is 10-220 nM and the detection limit is 0.54 nM.?2?Using the reductive nature of tannic acid,AuNPs and AgNPs are reduced from Au³⁺and Ag⁺,to produce Ag/TA/AuNPs/GCE.Due to the catalytic properties of AuNPs and AgNPs,H₂O₂ reduction can be directly catalyzed at the electrode.Therefore,the H₂O₂ reduction signal can be directly detected at the electrode.The detection range of Ag/TA/AuNPs/GCE for H₂O₂ was 2-5270?M,and the detection limit was 0.00936?M.The modified electrode continuously responds for 1600 s in a solution containing 0.5 mM H₂O₂,and its response current is almost unchanged,so the modified electrode has good stability.In the presence of five-fold interferences,the modified electrode still produces a very sensitive response to H₂O₂.?3?The magnetic nanoparticles Fe₃O₄ are easily separated from the solution under an applied magnetic field.The tannic acid complex film was rapidly grown on the Fe₃O₄ surface,and the AuNPs were reduced and fixed in one step.The Fe₃O₄/Fe³⁺-TA/Au nanocomposite structure was prepared,and the strong catalysis and adsorption ability of organic dyes were exhibited.The catalytic rate for methylene blue is 0.018 s^-1,and the catalytic rate for rhodamine B is 0.0165 s^-1.And the materials are easy to separate without causing secondary pollution.