Preparation Of Phenylenediamine Carbon Dots And Fast Fluorescence Sensing Analysis Of Phosgene

Phosgene is a colorless and highly toxic gas.It was used as a chemical warfare agent in the World War I and caused a large number of casualties.Inhalation of phosgene into the human body will cause irreversible lung damage and endanger life.At the same time,phosgene occupies a very important position in industrial production.Whether it is accidental leakage in industrial production or being used by terrorists,phosgene will pose a threat to social public security and world peace.Therefore,it is very important to realize the trace,rapid and sensitive specific detection of phosgene.As an emerging nanomaterial,carbon dots(CDs)have attracted much attention due to their excellent optical properties,good biocompatibility,super resistance to photobleaching and low toxicity,and are widely used in chemical sensing,bioimaging,drug transportation,etc.At present,there are no reports about carbon dots that can be used for phosgene sensing.Phenylenediamines are very easy to polymerize by themselves and are widely used carbon sources for preparing carbon dots,besides,they also contain amino groups which can specifically react with phosgene.Therefore,this article explores the application of carbon dots prepared from o-phenylenediamine,mphenylenediamine and p-phenylenediamine in the detection of phosgene.The specific content is as follows:1.Preparation of fluorescent carbon dots based on o-phenylenediamine and the application in the detection of phosgeneMaking o-phenylenediamine as the carbon source,green fluorescent carbon dot o-CDs were prepared by solvothermal method,and the morphology,chemical bonds and main functional groups of the carbon dots were characterized by Transmission Electron Microscope(TEM),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FT-IR).They proved that the carbon dots are successfully prepared and the surface contains a lot of amino groups.Because it is rich in amino groups,o-CDs can be used as amines to convert triphosgene to phosgene and realize the detection of phosgene.The carbon dots were green fluorescence in the acetonitrile solution,after encountering phosgene,the amino group reacts with phosgene to form the carbamate substance m-CDs-TP,and the green fluorescence disappeared.The entire reaction process can be completed in 5 seconds,and the detection limit is as low as 0.4167 μM.In addition,the headspace fluorescence method was used to explore the detection of gaseous phosgene by o-CDs,and 5 μM phosgene within 2 minutes can cause fluorescence quenching of carbon dots.2.Preparation of fluorescent carbon dots based on m-phenylenediamine and the application in the detection of phosgenem-phenylenediamine was prepared into carbon dot m-CDs by solvothermal method,and its morphology,chemical bonds and main functional groups were characterized by TEM,XPS and FT-IR.The spectroscopic properties,selectivity and reaction time of the reaction of m-CDs with phosgene were explored by ultravioletvisible spectrophotometer and fluorescence spectroscopy.After m-CDs reacts with phosgene,the blue-violet fluorescence is converted into cyan fluorescence,the response time is shorter(2 s),the detection limit is lower(11.80 nM),and the 3 μM gaseous phosgene detection can be detected within 90 s.Compared with a single"turnon" or "tun-off" fluorescent signal detect model,the ratiometric fluorescence signal generated by m-CDs detecting phosgene has more accurate detection results.Therefore,m-CDs are more practical in practical applications.3.Preparation of fluorescent carbon dots based on p-phenylenediamine and the application in the detection of phosgeneCarbon dots(p-CDs)prepared by the solvothermal method of pphenylenediamine realize the colorimetric and ratiometric dual signal detection of phosgene.The morphology,chemical bonds and main functional groups of p-CDs were characterized by TEM,XPS and FT-IR,which confirmed that the surface of p-CDs has a large number of amino groups,so that p-CDs can realize the detection of phosgene.After p-CDs reacted with phosgene,the color of the solution changed from pale yellow to lavender,and the fluorescence of the solution changed from yellow fluorescence to dark red fluorescence.The color change could be observed within 2 s,and the detection limit was 59.4 nM.The headspace fluorescence method verified that p-CDs can also achieve rapid,sensitive and specific detection of gaseous phosgene.Besides,the ratiometric fluorescence signal makes the detection result more accurate,and the colorimetry makes the experimental result easy to observe with the naked eye.This makes p-CDs more convenient and practical in detection applications,and can be used as a phosgene detection kit to achieve real-time,sensitive and specific detection of phosgene.