The Construction Of Ratiometric Fluorescent System Based On O-phenylenediamine And Its Application In Analysis And Detection

Nowadays,with the rapid development of people’s living standards,as life becomes more and more convenient,people are also facing various environmental pollution and health problems.Environmental pollutants such as organic pollutants,heavy metal ions or components related to human health such as vitamins and antibiotics are the focus of current analysis and detection.Therefore,it is very important to develop efficient and convenient analytical methods to detect these components that affect the environment or human health.In this context,the level of analysis technology has developed rapidly,and various analysis methods emerge in endlessly and have their own unique advantages.However,most analysis methods are limited due to the shortcomings such as high cost and complex operation.Among all analytical methods,fluorescence spectrometry stands out because of its low cost,simple operation,excellent selectivity,fast and accurate results.It has become one of the best analytical methods.In recent years,it has been widely used in many fields,such as medicine,catalysis,environmental monitoring,food analysis and so on.However,so far,most fluorescence methods use fluorescence analysis with only a single emission peak,which is easily affected by the fluctuation of the test environment.In contrast,the ratiometric fluorescence analysis system can provide more accurate measurement results by calculating the intensity ratio of two fluorescence peak signals,which can better resist the interference of external environment and make the results more stable and accurate.O-phenylenediamine(OPD)is an organic substance with simple structure,flexible and diverse properties and low toxic.Thus,it often used to synthesis fluorescent material,or as a substrate for constructing a fluorescence analysis system.In this thesis,using OPD as substrate to design different fluorescence analysis system to detect2,4,6-trinitrophenol(TNP)and ascorbic acid(AA,Vitamin C).And in-depth research on its sensing mechanism,then further explores the application of the analytical system developed in real water sample,living cell,human serum and fruits.The specific work is as follows:(1)Carbon dots(CDs)with dual emission property can provide a convenient way to construct a ratiometric fluorescent sensor,which contributes to accurate determination of the target analytes.In this work,we present a simple and effective route to prepare dual emission CDs(DE-CDs)through the solvothermal reaction of o-phenylenediamine and ethanolamine.Under the excitation of UV light,DE-CDs not only show two distinguishable fluorescent emission peaks(430 nm,550 nm),but also exhibit good water solubility and ratio fluorescence stability.The synthesized DE-CDs were employed as a ratiometric fluorescent sensor for the sensitive and selective detection of 2,4,6-trinitrophenol(TNP).Under optimal analysis conditions,a good linear relationship was obtained with the TNP concentration range from 0.2 to 50 μM and the limit of detection can reach 50 n M.The proposed method was applied successfully for the TNP detection in real water samples with recoveries of 86.8-116.3%.Furthermore,cell imaging experiments confirm the feasibility of visualizing intracellular TNP in live He La cells.(2)Copper oxide nanoparticles(CuO NPs)as nanozymes have received extensive attention due to their numerous advantages such as water solubility and biomimetic effects.In this work,we combined the inherent oxidase and ascorbate oxidase mimetic activity of CuO NPs to construct a ratiometric fluorescence system for the detection of ascorbic acid(Vitamin C,AA)in serum and fruits.By feat of the dual mimic nanozymatic activity of CuO NPs,the sole substrate o-phenylenediamine(OPD)can be catalyzed to attain yellow fluorescent 2,3-diaminophenazine(ox OPD),while oxidized AA will react with the pristine OPD to form blue fluorescent product.This method has a sensitive response to AA with a good linear relationship in the concentration range of1-150 μM and low detection limit of 0.16 μM.Practical sample detection of AA in human serum and fruits can be realized reasonably with the recovery rates between84.83%-87.28% and 88.53%-113.1%,respectively.More conveniently,the method can be successfully used for scanning measurement analysis through the associated application(Color Assist)on smartphones and portable UV lamps.