| Uranium is a natural radioactive element that plays an important role in nuclear fuel and weapons.The main fuel used in nuclear power plants is mainly uranium at present.However,due to the radioactive and chemical toxicity of uranium,the development and utilization of uranium will also cause great harm to the environment and organisms.Therefore,the rapid detection of uranium in environmental water bodies as well as in cells is crucial.At present,there are many methods that can conduct very accurate and sensitive quantitative and qualitative analysis of uranium,but these methods are still facing with difficulties in practical application caused by expensive instruments,complex operation and high professional training requirements,and inability for meeting portable and rapid detection,etc.Aggregation-induced Emission(AIE)is a fluorescence phenomenon that is quite opposite to the properties of Aggregation caused quenching(ACQ).Materials with AIE property can exhibit continuously enhanced fluorescence as the molecules accumulate,with some accompanied by fluorescence wavelength shifts.Most AIE organic molecular probes tend to produce molecular aggregates in water-based samples,resulting in high fluorescence quantum yields,so the use of organic solvents can be reduced or avoided.Thus,developing highly sensitive AIE materials with specific identification of uranium has great application prospects for the rapid detection and pollution warning of radionuclide contamination in environmental water bodies.On the other hand,Portable fluorescent fiber sensor(PFFS)has the characteristics of small volume,low cost,high flexibility,light quality,stable material properties and high sensitivity.Compared with the traditional detection method of large instruments,it has the advantages of in-situ pollution monitoring.In this study,to addresses the current application limitations of uranium detection in environmental samples,a new AIE fluorescent probe with good biocompatibility and high selectivity based on Triphenylamine(TPA)has been developed,and a PFFS has been constructed,which realized the highly sensitive and visual detection of uranium in environmental water and intracellular uranium imaging.This study has wide practical applications for in situ monitoring of environmental uranium pollution in multiple scenarios and early warning of uranium radiation hazards in vivo.The main research contents of this paper are as follows:1.By introducing Salicyaldehyde Schiff base molecule into TPA molecules,a highly sensitive fluorescent probe TPA-SP with AIE properties was designed and synthesized for the field detection of uranium in complex samples(including uranium wastewater,Pearl River water and He La cells).The photophysical properties,intracellular experiments,uranium identification mechanism,and practical analytical test performance of TPA-SP has been systematically investigated.Results show that TPA-SP has high sensitivity and selectivity for UO22+ and good resistance to interference over a wide range of p H.In the concentration range of 0.05-1 μM,a good linear relationship is calculated with the LOD of 39.4 n M(9.38 ng/L).And it also showed good analytical performance in real samples.2.Firstly,A new type of fluorescent fiber sensor system was built by connecting the light source,Y optical fiber,flanged adapter,optical filter and its bracket and optical fiber spectrometer in series.With the flange adapter,the fiber probe is replaceable and then carry out quantitative detection of different target objects.After testing,the fiber sensor system has a good response of fluorescent signal to fluorescent substances,which can be used for further experimental exploration.Second,To further improve the detecting system and achieve the detection of uranium in pure water samples(without additional organic solvents phase),in this study,a water-soluble AIE probe TPP-BAC was designed and synthesized by introducing the Pyridine quaternary ammonium cation and amide group into the TPA-based fluorescent molecule.The novel probe TPP-BAC has high selectivity,good biocompatibility,and was successfully connected in series with the FL-2700 fluorescence spectrometer and PFFS to built the TPP-BAC @ FL-2700 sensor and the novel TPP-BAC @ PFFS sensor,respectively.The two sensors were used for the field detection of uranium in complex environmental samples(including uranium leachate,South China Sea seawater and He La cells).The photophysical properties,intracellular experiments,uranium identification mechanism,and analytical test performance in practical applications of TPP-BAC were systematically investigated.Results show that TPP-BAC has high sensitivity and selectivity for UO22+ and good anti-interference ability against different anions under a wide range of p H.In the concentration range of 0.05-6 μM,the fluorescence emission intensity change of probe TPP-BAC was well linear with the UO22+ concentration,with the LOD being20.13 n M(4.79 ng/L)and 134.36 n M(31.98 ng/L),respectively,and showed good analytical performance in real samples. |
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