Iron-doped Carbon Dot Catalysis RRS/SERS Dimode Aptamer Determination Of Bisphenol A

Since the arc discharge method was used to purify carbon nanotubes（SWNTs）from carbon dust and discovered the existence of carbon dots（CDs）,the preparation and utilization of CDs have sprung up.CDs have strong fluorescence and good biocompatibility.They are commonly used as bioimaging probes and biosensors.They are widely used in analytical chemistry,especially in environmental analysis and biological analysis.However,due to its poor electron transfer performance,the application of CDs is still limited.Surface functionalization and chemical heteroatom doping can effectively improve the photoluminescence properties of CDs and expand their application range.This paper focuses on the preparation and application of iron-doped carbon dots(CD_Fe).At present,known methods for preparing CDs preparation methods include the top-down method with the main method of destroying the structure of the carbon source,and the bottom-up method that uses molecular precursors as the carbon source to prepare CDs through carbonization,condensation,and polymerization.The hydrothermal method is the most effective and most extensive technology for synthesizing CD_Fe,but the hydrothermal method that has been reported so far usually requires complicated treatment of the carbon source,or its reaction conditions are relatively complicated.Therefore,this article is devoted to developing a simple and easy one-pot hydrothermal method to prepare CD_Fe.So far,it has confirmed that gold-doped carbon dots(CD_Au)can catalyze the amplification of 3,3’,5,5’-tetramethylbenzidine（TMB）-H₂O₂reactions.In our research,we found that CD_Fe has excellent optical properties,and at the same time,due to the doping of iron,CD_Fe has excellent catalytic properties.Therefore,we designed a SERS/RRS dual-mode sensor to identify trace amounts of BPA,which was based on the catalytic amplification effect of CD_Fe on HAu Cl₄-ethanol/glucose/glycerol/ethylene glycol nanoreaction and the specific recognition effect of aptamer on bisphenol A（BPA）,combined with the SERS/RRS dual function indicator of the nanoreaction product.And the specific research work are as follows:In chapter 2,the monomer ferrocene（Fer）was used as a precursor to produce iron-doped carbon dots(CD_Fe)by muffle furnace hydrothermal method.The catalytic effect of CD_Fe on the HAu Cl₄-ethanol/glucose/glycerol/ethylene glycol nanoreaction was used as an evaluation standard.According to the standard,the preparation conditions of CD_Fe have been optimized,including Fer dosage,reaction time and reaction temperature on the properties of CD_Fe catalytic effect.Subsequently,the optical properties of CD_Fe were studied using fluorescence spectroscopy,resonance Rayleigh scattering spectroscopy,ultraviolet-visible spectroscopy,infrared spectroscopy,and surface enhanced Raman scattering spectroscopy.The structure of CD_Fe was further characterized by X-ray powder diffraction（XRD）,high resolution transmission electron microscopy（HRTEM）and X-ray photoelectron spectroscopy（XPS）.Finally,the best preparation conditions for CD_Fe and CD_Fe with the best catalytic performance were obtained,which laid the foundation for its application in the catalytic amplification of nanoreactions.In chapter 3,BPA was selected as an analyte,which was regarded as a typical endocrine disruptor,can cause reproductive disorders,cancer and sexual growth-related diseases,posing a serious threat to human health.Therefore,it is urgent to establish a rapid,sensitive,and simple method for the determination of BPA.In this paper,based on the aptamer-mediated iron-doped carbon dot catalyzed HAu Cl₄-ethanol/glucose/glycerol/ethylene glycol nanoreaction,a new SERS/RRS dual-mode detection method for BPA was established.The results show that CD_Feexhibits a strong catalytic effect on HAu Cl₄-ethylene glycol nanoreaction,which could generate purple gold nanoparticles（Au NPs）with resonance Rayleigh scattering（RRS）signals and surface enhanced Raman scattering（SERS）effects.After the addition of BPA aptamer（Apt）,it could encapsulate CD_Fe through intermolecular interaction,thus inhibiting its catalytic action,resulting in the reduction of Au NPs generated and the reduction of RRS and SERS signals of the system.With the addition of BPA,Apt was specifically combined with BPA,and CD_Fe was re-released to restore the catalytic ability,the generated Au NPs increased.Then the RRS and SERS signals of the system were recovered,and their increment was linear with the concentration of BPA.Thus,the quantization of 0.1-4.0 n M（RRS）and 0.1-12.0 n M（SERS）BPA were realized,and the detection limits were 0.08 n M and 0.03 n M,respectively.At the same time,we used molecular spectroscopy and electron microscopy to study the CD_Fe-HAu Cl₄-ethylene glycol indicator reaction,then proposed a reasonable CD_Fe catalytic reaction mechanism.