Study On New Spectral Detection Methods Of Bisphenol A And Mercury In Environmental Water Samples

Chapter 1:Firstly,the research background,significance and current status of the detection of bisphenol A?BPA?and mercury ions(Hg²⁺)in environmental water samples are described.Secondly,the technologies and related materials involved in the establishment of new hygienic detection methods for detecting BPA and Hg²⁺are introduced,including resonance light scattering technology,resonance fluorescence technology and fluorescence analysis method.Materials such as aptamer,nitrogen-doped carbon dots?N-CDs?and carbon dot/copper nano-cluster dual emission probes?CDs-CuNCs?.Finally,the research contents of this article are expounded.Chapter 2:In the appropriate concentration of H₂SO₄ medium,trace BPA could promote the oxidation of fluorescein?FL?by KBrO₃.Under the condition of KBrO₃ excess,BPA were also oxidized by KBrO₃.And their reaction products?or after protonation?could form two kinds of electrically neutral ion association compounds with bromate ion rapidly,resulting in the increase of molecular size.There were more nonpolar groups?benzene rings?in the molecules of the two kinds of large size electrically neutral particle association compounds,so the two association molecules could aggregate to form larger aggregates through van der Waals force and hydrophobic force,resulting in the intense enhancement of resonance light scattering intensity(I_RLS)of the system.The increased value of RLS??I?was linearly correlated with BPA content in the range of 1.7×10^-72.0×10^-5 mol/L.The correlation coefficient was r=0.9993,and the detection limit was 0.83×10^-7 mol/L.The experimental results showed that this method has a good application prospect in the detection of BPA in water samples.Chapter 3:Based on the accurate recognition and strong affinity of BPA aptamer?#3-aptamer?to BPA molecules,a new method for detecting trace BPA in environmental water was established by using the interaction of BPA+#3-aptamer+PDDA+AuNPs+Rh6G.The experimental results showed that the change values of resonance fluorescence intensity??F?of the reaction system increases with the increase of BPA content in the sample.Under the best experimental conditions,there was a good linear relationship between?F and the concentration of BPA in the range of 5.0×10^-95.5×10^-7 mol/L.?F=0.8252 C_BPA(×10^-9 mol/L)+4.469,r=0.9973,and the detection limit of BPA was 1.4×10^-9 mol/L.Chapter 4:A high fluorescence quantum yield nitrogen doped carbon dots?N-CDs?was synthesized by microwave with citric acid as carbon precursor and o-phenylenediamine as nitrogen source.It's structure and properties?water solubility,good stability and high fluorescence quantum yield?were characterized by spectroscopy,TEM and XPS.Based on the specific quenching of the fluorescence of N-CDs by Hg²⁺,a new sensitive method for the determination of Trace Mercury in environmental water samples was established.Under the best experimental conditions,there was a linear correlation between the fluorescence change??F?of the reaction system and the concentration of Hg²⁺(C_Hg²⁺)in the range of1.0⁸00 nmol/L.The linear regression equation was:?F=4.544 C_Hg²⁺?nmol/L?+178.7?r=0.9985?,and the LOD of Hg was 0.36 nmol/L.Chapter 5:Using BSA as template and hydrazine hydrate as reducing agent,a red-emitting copper nanocluster material with good spectral properties was synthesized by microwave method.Blue-emitting carbon dots?CDs?were synthesized using citric acid and cysteine as materials by microwave.The structure and properties?such as dual emission and possible groups on the surface?of the optical material were characterized by UV,fluorescence,XPS and TEM.Based on the principle that Hg²⁺could quench the fluorescence of the Cu nanoclusters with little affect on the fluorescence of the carbon dots,a dual emission fluorescence probe?CDs-CuNCs?of Hg²⁺was constructed in combination with the blue emission carbon dots,and a new method for the detection of trace mercury in environmental water samples was established.Under the best experimental conditions,the concentration of mercury ion in the range of 0.20-50?mol/L was linearly correlated with the fluorescence ratio.I_415/635=0.023 C_Hg²⁺??mol/L?+0.504,r=0.9963,and the detection limit was 0.060?mol/L.