Fluorescence And Resonance Rayleigh Scattering Spectroscopy To Detect Chiral Drugs In The Environment

Chirality is one of the essential properties of nature,and the corresponding chiral enantiomers also play an important role both in the human and in the natural environment.In the process of material cycle and energy flow in the ecological environment,chiral enantiomers play an extremely important role and affect various life activities and processes.The use of chiral pesticides can effectively kill pests and improve the yield and quality of crops and greatly alleviate the food crisis.The application of chiral drug has enabled mankind to conquer many diseases and brought hope to many lives.The addition of chiral food additives makes food have a longer shelf life and more versatile preparation.However,due to insufficient understanding of chiral substances,many serious problems have arisen in the application process.Enantiomers of chiral pesticides may cause great latent crises to the human body and the ecological environment.The"thalidomide tragedy"is a major potential risk of fetal teratogenicity caused by the use of enantiomers of chiral drugs.The use of enantiomers of chiral food additives makes the food environment more complex and induces many unknown diseases in the human body.This is the selective and negative effect of chiral enantiomers on the ecological environment,so the use of chiral substances should be more cautious.Different enantiomers of chiral drugs have different pharmacological effects in the human body,while the enantiomers of chiral drugs released and abandoned in the environment will have selective and negative effects on the ecological environment.Based on this,it is very important to identify and analyze the chiral drugs remaining in the ecological environment,understand the selective effects and biological effects of different enantiomers on the environment,explore the selective action mechanism of chiral enantiomers in the environment,and establish a quick chiral identification and analysis method for population health and natural environment protection.In this paper,propranolol and ephedrine,two chiral drugs remaining in the environment,were used as the research object,and the corresponding aptamers of propranolol,algal red B?Ery B?and gold nanoparticles?AuNPs?,were used as the detection probes.Using fluorescence spectroscopy and resonance Rayleigh scattering spectroscopy as the main detection methods,the interaction between the research object and the detection probe and the influence on the resonance Rayleigh scattering spectrum,fluorescence spectrum and absorption spectrum of the detection system were investigated.In this paper,the optimal reaction conditions are discussed,and the fluorescence spectrum and resonance Rayleigh scattering analysis methods for S-propanolol and ephedrine are established.The analysis conditions and reaction mechanisms of the two research objects are discussed.The method is applied to the test of actual samples and satisfactory results are obtained.This academic dissertation was completed with the support of the National Natural Science Foundation of China?Nos.21175015,21475014?.The main research contents are as follows:1.Screening of propranolol aptamers based on resonance Rayleigh scattering and GO-SELEX method.S-propranolol?S-Prol?,also known as“Naixinan”,is a commonly used cardiovascular drug in the clinic.However,the other enantiomer contained in the drug has certain side effects.Based on this situation,the detection of S-propranolol in pharmaceuticals and the natural environment has great practical significance.As an emerging detection probe,aptamers have great affinity and specificity for targets.The aptamer has great potential as a resonance Rayleigh scattering probe to detect S-propranolol.Therefore,the GO-SELEX method using graphene oxide?GO?as the adsorption platform combined with the resonance Rayleigh scattering method successfully screened the aptamer of S-propranolol which showed a low affinity for the other enantiomer R-propranolol.Ten rounds of products were obtained during the screening process,and the best screening products were obtained by testing 6 to 10rounds of products.After sequencing and analyzing the products,31 aptamer preparations were obtained,and the aptamer sequences with the strongest affinity were obtained after detection.2.Resonance Rayleigh Scattering method with Aptamer as Light Scattering Probe for Detection of Chiral Drug Propranolol.Using the aptamer in Experiment 1 as a light scattering probe,a spectral detection method based on resonance Rayleigh scattering technology was established to detect the chiral drug S-propranolol.The reaction system was examined using resonance Rayleigh scattering and UV-VIS absorption spectroscopy to discuss the reaction mechanism between aptamer and target.Under the optimal conditions,when the aptamer,S-propranolol and R-propranolol exist alone,the RRS strength of the system is weak.However,the aptamer coexisted with S-propranolol,and the RRS intensity of the system changed significantly.When the aptamer and R-propranolol coexisted,the RRS intensity of the system did not change significantly.Therefore,it should be that the aptamer binds to S-propranolol at pH=7.4 to form aggregates of particles,leading to an increase in RRS strength.Under the optimal conditions,the RRS intensity of the system increases with the concentration of S-propranolol in the range of 5-275 nmol/L as the target concentration increases.The detection limit was0.5 nmol/L,and the correlation coefficient was 0.9931.Therefore,a new method for detecting S-propranolol has been successfully established,and satisfactory results have been obtained in drug detection and urine sample detection.3.Rapid detection of chiral drug ephedrine by the resonance Rayleigh scattering method using Ery B for light scattering probeEphedrine and pseudoephedrine which are chiral enantiomers commonly used clinically have different pharmacological actions and treatment effects due to their chiral nature.In the presence of Pd²⁺,the reaction system of Ery-Pd²⁺have a strong RRS intensity.Adding ephedrine into this system would make the RRS intensity reduce,but pseudoephedrine could not produce the phenomenon.The chiral recognition of these enantiomers could be achieved according to this spectral difference.At the same time,the reduction of RRS strength of the reaction system is proportional to the concentration of ephedrine.Under optimized conditions,the linear range is 40-960 ng/mL,and the detection limit is 3.9 ng/mL.A new method for the rapid detection of ephedrine enantiomers can be established.Based on this assay,a new method for the determination of the chiral enantiomers of ephedrine and pseudoephedrine can be developed.4.Rapid detection of chiral drug ephedrine using resonance Rayleigh scattering method based on gold nanometer as light scattering probeUnder alkaline conditions,ephedrine increased the RRS intensity of the AuNPs-Ce³⁺detection system,and pseudoephedrine decreased the RRS intensity of the AuNPs-Ce³⁺detection system.Based on this phenomenon,A resonance Rayleigh scattering method using AuNPs-Ce³⁺as a light scattering probe was developed to detect the chiral enantiomers of ephedrine and pseudoephedrine simultaneously.The mechanism of this detection method was discussed by analyzing the RRS spectrum and the absorption spectrum of the AuNPs-Ce³⁺detection system.Under the optimal experimental conditions,the linear range of ephedrine is 20-920 ng/mL,and the detection limit is 1.9 ng/mL.The method has been applied to actual samples detection,and good results have been obtained.