Peroxyoxalate/Carbon Dots Chemiluminescent Reaction For Application Of Visible Detection

As a new kind of carbon-based fluorescent nanomaterials,carbon dots?CDs?have been widely studied and applied in sensing,bioimaging,drug delivery,medical diagnosis,photocatalysis and electrocatalysis field owing to their good biocompatibility,remarkable photostability,low toxicity,and easy to modification.A variety of carbon dots such as nitrogen-doped,sulphur-doped,phosphorus doped,boron-doped,fluorine-doped and iron-doped CDs have been synthesized by diverse carbon precursors and different synthetic method.These resulting CDs inherently possess unique chemical structures and various surface organic functional groups including oxygen-based functional groups such as carboxylic?-COOH?and hydroxyl?-OH?groups,nitrogen-based functional groups such as pyridinic-N,pyrrolic-N and amino groups?-NH₂?and sulphur-based groups.Therefore,the CDs have more surface active sites to combine effectively with metal ion or indirectly coordinate with some nonmetallic ions.Additionally,CDs are easy to surface modification by the carboxylic and amino groups.Based on the excellent properties,CDs can be designed as a promising sensor for the detection of various metal ions(such as,Hg²⁺,Ag⁺,Cu²⁺,Au³⁺,Pt²⁺,Pd²⁺,Co²⁺,Cr?VI?),nonmetallic ions(such as H⁺,F^-,I^-,CN^-,ClO^-,S^2-,PO4^3-,C₂O₄^2-)and biomolecules?such as,amino acid,dopamine,ascorbic acid,glucose,DNA and protein?.Carbon dots have been applied to the chemiluminescence?POCL?system of peroxydicarbates.1.A visible luminous sensing platform was studied by using peroxyoxalate-based chemiluminescence?POCL?system and fluorescent carbon dots?CDs?.A new CDs were synthesized by hydrothermal treatment of pitaya fruit,which displayed good fluorescence property and high sensitivity and selectivity toward Fe³⁺attributed to the surface group of hydroxyl and carboxyl groups.Fluorescent Fe³⁺sensor was developed based on fluorescence quenching of CDs,which displayed high sensitivity and selectivity.In addition,a visible luminous sensing platform was explored using POCL/CDs system,in which CDs acted as capturers and emitters for Fe³⁺identification and luminescence signal.Using this technique,Fe³⁺assay can be performed by simple mix of several solution,and don?t have to rely on large measuring instrument.It turns out that the proposed method have good sensitivity,selectivity and potential application in sensing.2.Red nitrogen-doped carbon dots?N-CDs?were synthesized by hydrothermal synthesis using citric acid and neutral red as raw materials and studied their application in chemical sensing.The resulted carbon dots shows red fluorescence in both solid and aqueous solutions,with the maximum excitation wavelength at 530 nm.The N-CDs display excellent photostability in aqueous solution.The strongest fluorescence is obtained at pH 3.0.The results in TEM,XPS and FTIR characterization reveal that the N-CDs have narrower particle size distribution and plentiful oxygen and nitrogen-containing functional groups on their surface.The carbon dots were acted as luminescence reagent and used for the fabrication of peroxyoxalate-based chemiluminescence sensing platform.The results indicated that the peroxyoxalate/N-CDs system display bright red chemiluminescence.In addition,the properties and application in hydrogen peroxide detection of the chemiluminescence system was further studied.