Chemiluminescence Mechanism And Application Of Small Molecule Compounds Sensitized By Carbon Quantum Dots

As one of the most promising fluorescent nanomaterials in the 21st century,carbon quantum dots?CQDs?have unique optical properties and quantum properties such as adjustable emission peaks,stable fluorescence,and no-light scintillations.They have been successfully applied in many fields such as environmental detection,vivo imaging,biological probes and optoelectronic devices.At present,the research on carbon quantum dots focuses on the field of living or cell imaging and catalysis.The study of the chemiluminescence system participated by CQDs has become a research hotspot,but the research about CQD chemiluminescence system mechanism is still at a preliminary stage.The focus of this article is to use simple methods to synthesize CQDs to construct new chemiluminescence systems,and analyze and discuss its luminescence mechanism and realize detection and application of small molecule compounds.The main contents of the full text include the following three parts:?1?Reference from the literature we choose L-serine,PEG₁₅₀₀ and glycerol as raw materials to synthesize CQD.The carbon quantum dots were synthesized by a simple and fast microwave-assisted method,and then ultraviolet-visible absorption spectrophotometer,fluorescence spectrophotometer,transmission electron microscope and nanometer particle size analyzer were used to characterize its morphological,optical and parti chemiluminescence e size sizes.And apply them to the construction of the following new chemiluminescence systems.?2?The author used the above-mentioned synthesized CQD to add to the KMnO₄-cysteine alkaline chemiluminescence system,and found that the system strength was enhanced by about 170 times,thereby constructing a KMnO₄—CQD—cysteine alkaline chemiluminescence system to achieve the detection of cysteine The detection limit of cystine was 2×10^-77 mol L^-1,and the linear range from 3.0×10^-7 mol L^-1 to 6.0×10^-6 mol L^-1.Possible chemiluminescence mechanism that lead to the effect were elucidated by recording UV,fluorescence,and chemiluminescence spectra and studying the effect of some radical scavengers.?3?The authors describe a chemiluminescence?CL?-based assay for the determination of bromate.The method is based on the use of a solution of carbon quantum dots?CQDs?and sulfite.Strong chemiluminescence?peak at 490 nm?is observed when bromate is injected into the solution.The chemiluminescence increases linearly in the 0.3?mol L^-1 to 10?mol L^-1 bromate concentration range,giving a 0.1?mol L^-1 limit of detection?at an S/N ratio of 3?.A possible chemiluminescence mechanism is suggested that involves a redox reaction between the CQDs,bromate and sulfite in the acidic medium.This leads to the formation of hole-injectedandelectron-injectedCQDs.Radiative recombination of oxidant-injected holes and electrons in the CQDs accounts for the occurrence of chemiluminescence.This mechanism contradicts the previous assumption that the transfer of energy occurs from SO₂^*to the CQDs.Although nitrite may interfere in the determination of bromate,its effect can be eliminated by adding sulfamic acid.The assay is sensitive and represents a new tool for the determination of bromate,which is a carcinogen.