Study On Phosgene Fluorescent Probes And Detection Devices

Phosgene is a kind of severe asphyxiating toxic gas.At the same time,it is also an important intermediate in organic synthesis.It is widely used in the synthesis of dyes,plastics,pesticides and medicine.The development of fast and sensitive detection methods and portable in-situ devices to meet the actual detection requirements are of great significance for real-time monitoring of phosgene and maintaining public safety.The fluorescent probe has the characteristics of well designability,high sensitivity and visualization capability,which has significant advantages in real-time detection.In recent years,the detection method of phosgene based on fluorescent probes has attracted extensive attention.Developing new phosgene fluorescent probes to improve the sensitivity,selectivity and response speed and constructing detection devices that can be used in practice are the hotspots in the research field of phosgene probes.For practical application requirements of phosgene detection,three fluorescence detection models including turn-on,turn-off and ratio for phosgene detection have been constructed by using two rhodamine derivatives and 2,3-diaminophenazine.A new reaction site for phosgene detection based on amidoxime is proposed,which greatly improves the selectivity of phosgene detection.It provides a new strategy for the design of new phosgene fluorescent probe.Based on the demand of real-time detection of gaseous phosgene in real life,the film droplets and a portable fluorescent detection pen based on the rapid reaction at gas-liquid interfaces were designed by evaluating the effect of different types of fixed forms of the probe.The designed liquid sensors have the advantages of fast reaction at gas-liquid interfaces,and the solid polystyrene film could be employed in long-time imaging phosgene after solvent volatilization.Compared with traditional solid-state detection devices(test strips,electrospun fiber and polymer films),liquid detection devices overcome the shortcomings of slow solidgas reaction and low sensitivity,which provides a new idea in the development of phosgene device.The specific research contents of this paper are as follows:1.Development of a rapid turn-off fluorescence detection method of phosgene and liquid film droplets detection device based on 2,3-diaminophenazineUsing 2,3-diaminophenazine(P1)as a fluorescent probe,a turn-off phosgene realtime detection method was constructed based on the reaction characteristics of its ophenylenediamine unit with phosgene.The linear range of phosgene detection in solution is 0-5 μM,and the detection limit is 99.78 nM.Through the study of the probe loading mode,a liquid phase phosgene detection device is constructed.The device overcomes the problem of slow response of solid-state detection devices.The visual change from yellow green to orange can occur within 2 minutes,and the minimum amount detected by the naked eye is 5 ppm,which meets the needs of actual detection.In this study,a colorimetric and fluorescence turn-off visual detection method constructed by commercial 2,3-diaminophenazine.It has the characteristics of readily available and instantaneous response,which is expected to be applied in the practical rapid detection of phosgene.2.Development of a ratiometric phosgene fluorescence detection method and liquid film droplets detection device based on new reaction site of amidoximeA rhodamine derivative(P2)with the amidoxime structure was constructed by a one-step reaction at room temperature using rhodamine 800 and hydroxylamine.Phosgene can produce a specific recognition response with the amidoxime site to produce cyclic oxadiazole product with a redshift fluorescence emission,which can be completed within 2 s.Based on the fluorescence spectrum changes caused by the above specific reaction,a ratio phosgene fluorescence detection method is constructed.The concentration of phosgene in the range of 0-50 μM with a low detection limit of 34.65 nM.Compared with the reported method,P2 can distinguish phosgene from other active acyl chloride compounds which shows better selectivity.At the same time,the liquid film device based on P2 can realize fast and sensitive colorimetry and fluorescence detection with a detection amount by the naked eye of 5 ppm.In this study,a new reaction site for phosgene detection based on amidoxime was proposed for the first time,which provides a basis for the design of phosgene reaction site.3.Development of a turn-on phosgene fluorescence detection method and a portable fluorescent detection pen based on the ring-open reaction of rhodamineAn ultrasensitive phosgene probe P3 was designed based on the ring-open reaction of rhodamine.After the action of phosgene,probe P3 recovers the fluorescence of rhodamine,which can realize the colorimetric and turn-on fluorescence detection of phosgene.The fluorescence intensity of P3 has a good linear relationship with the concentration of phosgene in the range of 2-7 μM,and the detection limit is 26 pM.The turn-on detection mode has no interference with background fluorescence and improves the detection sensitivity,which is more conducive to the visual detection of phosgene.Through the blending of probe and polystyrene and the loading of refill,a portable fluorescent detection pen is developed.It is successfully used for colorimetric and fluorescence detection of phosgene gas by naked eyes with a detection amount of 2 ppm.The detection pen is simple to operate and "write to test",which can also be combined with smartphone RGB analysis to realize the in-situ rapid quantitative analysis of phosgene.It provides a reference and basis for the real-time in-situ detection of phosgene.