The Detection Of Trace Chiral Pollutants In Environmental By Fluorescence And Resonance Rayleigh Scattering Spectrometry

Chirality widely exists in nature,Chiral enantiomers,whether artificial or natural,play a wonderful role in the natural environment and dominate the mystery of life.The using of chiral pesticides increases the output of grain,so solving the problem of human food and clothing,the chiral drugs can help people overcome some difficult diseases,and the chiral additives can improve the quality and stability of food.However,everything have two sides,chiral pesticides have have caused bad effect on ecological environment and human health.Some chiral drugs have led to the birth of abnormal children.The massive use of chiral additives has also result in adverse effect on food environment.Therefore,we named these chiral substances which harmful to human body and environment as chiral pollutants.Different enantiomers of chiral pollutants have different biotoxic effects,and their corresponding environmental behaviors including degradation and biological metabolism are also different.Therefore,it is necessary for the ecological environment and human health to analyze,separate and measure the chiral pollutants,know about the behavior and biological effects of different chiral pollutants in the environment,and characterize and explore the role and changes of chiral enantiomers.In this paper,the chiral drug Penicillamine and the chiral pesticides Malathion were choose as the research objects.We mainly investigated the reaction between research objects with probes which include gold nanoparticles?AuNPs?,quantum dots?QDs?and dye?Erythrosine B?using Resonance Rayleigh scattering and Fluorescence spectroscopy.The effect of spectral characteristics and the optimum conditions were discussed.Hence,the fluorescence spectrum for the determination of L-penicillamine and the resonance Rayleigh scattering spectrometry for the determination of Malathion based on two different resonance Rayleigh scattering probe were proposed.the reaction mechanisms were discussed in this paper,in addition,the new methods could be used in real samples to detect research object with satisfactory results.This paper was completed under the support of project of National Science Foundation of China?No.No.21175015;No.21475014?and Chongqing Postgraduate Innovation Project?CYS17290?,the main research details are as follows:1.Detection of Penicillamine based on the reaction between the target and N-acetyl-L-cysteine capped CdTe quantum dots for copper ionsD-Penicillamine?D-PA?,as the dominant enantiomer,is usually used in many clinical drugs,but the other enantiomer,L-penicillamine?L-PA?is a toxic enantiomer.Therefore,it is of great significance to analyze and detect L-PA in biomedical or environmental samples.CdTe quantum dots?CdTe QDs?were modified by N-acetyl-L-cysteine?NALC?as a novel fluorescent probes and was successfully utilized for the determination of L-penicillamine.The fluorescence of the CdTe QDs decreased significantly in the presence of cupric ions(Cu²⁺)due to the binding of Cu²⁺to NALC on the surface of the CdTe QDs,but the addition of L-PA immediately resulted in efficient fluorescence recovery of the modulated CdTe QDs.The experimental results showed that the pH of the buffer solution and the concentration of Cu²⁺affected the fluorescence intensity upon adding L-PA.Under the optimum conditions,the recovered fluorescence intensity was linearly proportional to the increasing L-PA concentration in the range of 2×10^-7-4×10^-6mol/L,with correlation coefficient R²=0.9980.So,a new,simple and rapid method for the determination of L-PA has been developed and its potential has been demonstrated in human serum samples and environmental samples with satisfactory results.2.A novel spectral method for determination of trace malathion using EryB as light scattering probe by resonance Rayleigh scattering techniqueA convenient and sensitive spectrophotometric method was proposed for determination of Malathion?Mala?using Erythrosin B?EryB?as a probe through the Resonance Rayleigh scattering?RRS?technique.The interaction between EryB,Pd²⁺and malathion in the system was investigated by fluorescence,RRS and UV-Vis spectroscopy.Under the optimum conditions,the RRS intensity of EryB,Pd²⁺and malathion was weak when exist in alone or any two kinds,however,the RRS intensity of the EryB-Pd²⁺-Mala system had a obvious enhancement due to Pd²⁺could interact with the hydrolysis products of Mala and EryB each other form a new complexes.At the same time,the fluorescence intensity of EryB was decreased significantly in the presence of Pd²⁺,and the fluorescence intensity of EryB-Pd²⁺system further decreased when Mala added,interestingly.So it was further proved that there was a forming complex in EryB-Pd²⁺-Mala system.Under the optimal conditions,the RRS enhanced intensity of the system was linearly proportional to the Mala's concentration in the range of 0.012-0.8?g/mL,and the LOD was 1.7ng/mL,with the correlation coefficient was R²=0.9960.So,a new method for determination of Mala was established and this method has been demonstrated in real sample with satisfactory results.3.Study on the determination of chiral pesticide Malathion in the environment by Resonance Rayleigh Scattering spectrometry based on L-His-AuNPs-Pd²⁺systemIn this study,L-histidine modified gold nanoparticles with blue fluorescence was synthesized by one-pot synthesis using L-histidine as modifier and reductant.L-histidine modified gold nanoparticles could be used as resonance Rayleigh scattering?RRS?probe to detect Malathion in the presence of Pd²⁺.under the optimum conditions,the fluorescence intensity could be quench by Pd²⁺,and the RRS intensity have obviously enhanced.When added Malathion into the above system,the degree of RRS enhancement was more obvious,but the fluorescence intensity have any change.Therefore,the resonance Rayleigh scattering method was proposed for determination of Malathion?Mala?.The effect of the concentration of Pd²⁺?buffer solution and some other conditions were discussed in this paper.Under the best conditions,the RRS enhanced intensity of the system was linearly proportional to the Mala's concentration in the range of 0.12-3.2?g/mL,and the linear equation was?I_RRS=543.72C_Mala+21.06,with the correlation coefficient was R²=0.9985.The reaction mechanism and the reasons for the enhancement of RRS were discussed.At the same time,this new method has been demonstrated in real sample with satisfactory results.