| Fluorescent probe method demonstrates many advantages such as high sensitivity,good selectivity,simple operation,low cost and etc.These advantages can make fluorescent probes to meet the requirements of the development of new detection technology.Hence,they can be applied in chemical and biological sensing,bioimaging,food security,medical diagnosis,and so on.Fluorescent probes based on metal organic frameworks(MOFs),semiconductor quantum dots(QDs)and carbon quantum dots(CDs)have good fluorescence properties and excellent photochemical stability.Therefore,it has become the most commonly used fluorescent probe for the rapid detection of food safety and the sensitive monitoring of clinical drug concentration.Part one:IntroductionFirstly,the basic concept of fluorescent probe was summarized;secondly,the classification and synthesis methods,basic properties,developing situation,application status of all kinds of fluorescent probes were introduced in detail;finally,the basis,significance and main content of this thesis are put forward.Part two:A ratiometric fluorescent probe based on metal-organic frameworks and quantum dots for selective detection of 6-mercaptopurine6-Mercaptopurine(6-MP)as an anti-metabolic purine antineoplastic agent,can inhibit many kinds of tumors.It is suitable for the treatment of acute lymphoblastic leukemia,chorionic epithelioma and malignant hydatidiform mole.Taking too much 6-MP can brings about serious side effects,therefore in clinical monitoring of 6-MP is particularly important.In this study,a dual emission ratiometric fluorescent probe was prepared by using NH2-MIL-5 3(Al)and MPA-CdTe QDs for the first time.The thiol group of 6-MP bind to the surface defects sites of MPA-CdTe QDs to form Cd-S bond,which can effectively enhance the fluorescence of MPA-CdTe QDs.Meanwhile,the fluorescence intensity of NH2-MIL-53(Al)is weakened due to the existence of the inner filter effect between NH2-MIL-53(Al)and 6-MP.Therefore,the rapid detection of 6-MP can be realized by monitoring the fluorescence intensity of the ratiometric fluorescent probe.Under the optimal condition,a good linear relationship between the ratios of the fluorescence intensity(I0/I)and the concentration of 6-MP within the range of 1-50 ?M was observed,the correlation coefficient is 0.9937,and the limit of detection is 0.15 ?M(S/N=3).The new method of detecting 6-MP has the advantages of high sensitivity and good selectivity and had been successfully applied to the detection of 6-MP in human urine samples.Part three:Fluorescent probe based on nitrogen doped carbon dots for detection of Sudan ?-?Sudan ?-? is a kind of artificial azo dye,are traditionally used for textiles,pigments,plastics,gasoline,printing inks,cosmetics and so on.Because of their low cost and bright color,Sudan ?-? are also attractive as food colorants.However,experiments have confirmed that Sudan dyes can cause rat liver and bladder cancer,so there is a potential risk to human beings.They are banned for food usage in most countries,including in the European Union.Therefore,the detection of Sudan ?-? has become an important part of food safety monitoring.In this study,according to the absorption spectra of Sudan?-? and the emission spectra of nitrogen-doped carbon dots(NC-dots)has a large degree of overlap,Sudan ?-? can significantly quench the fluorescence of NC-dots,thus we use NC-dots to construct fluorescent probe,and realize the simple,sensitive and rapid detection of Sudan ?-?.The probe has a broad linear range for Sudan ?-?,0.5-80?M(R2=0.9909),0.5-80?M(R2=0.9920),0.5-60?M(R2=O.9931)and 0.5-80 ?M(R2=0.9955)respectively,and the detection limits(S/N=3)are 0.16,0.14,0.12 and 0.16 ?M,respectively.In addition,we also used the fluorescent probe for rapid screening of Sudan red ?-? in chili powder samples with satisfactory results.It is proved that the constructed fluorescent probes has certain application potential in the field of food safety monitoring. |
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