| In recent years,with the continuous improvement of people’s living standards,more and more people have begun to pay attention to how to maintain a healthy body through diet and how to use food therapy to drive away diseases.The concept of natural,food-drug homology continues to gain popularity.As the relationship between the efficacy of natural product active ingredients and the health of the population is receiving increasing attention,coupled with the rich source of plant active ingredients themselves,various advantages such as antibacterial,anti-inflammatory,anti-cancer,anti-oxidant,and anti-tumor are prominent,making The fields of food,medicine and daily chemicals are becoming more and more widely used.However,there are also disadvantages.Compounds composed of plant active ingredients are generally more active and unstable in molecular structure;once the separation and extraction methods are improper,the molecular structure may change or the reaction may deteriorate;it is difficult to dissolve in cold water.The low bioavailability has led to higher expectations for the quality and content of some health care,skin care and even food products on the market.Therefore,it is necessary to develop fast and efficient analytical techniques to detect and identify the quality,content,and authenticity of active ingredients in market products.At the same time,it has greatly stimulated the research interests of experts and scholars from all walks of life.All kinds of ecological conditions in the environment influence each other in nature,restrict each other,form a specific ecological environment synthetically,and have an impact on plants.To study the environment is to discuss the relationship between human and environment.Natural plant active components are derived from various plants in the natural environment,but with the use of human,put into production and natural movement and other ways,it is inevitable that there is waste in the atmosphere,leakage phenomenon,resulting in low utilization of plant active components and environmental pollution.At the same time,because the source of plant active ingredients is rich,all kinds of activities are remarkable,people blindly pursue the value of"the more the better",and the material pole must be reversed to precisely cause harm to human beings and the environment.In addition,many bad merchants in turn for gimmicks,exaggerating its efficacy,due to the shortage of the market and the implementation of the phenomenon of substandard,resulting in many as the key ingredients of food,health products and cosmetics become inferior products,coupled with improper handling of serious pollution to the environment.In this paper,flavonoids curcumin,geraniol and docetaxel were used as research objects.At the same time,L-histidine-functionalized gold nanoparticles（L-His-AuNPs）with fluorescent effect and L-cysteine-modified carbon quantum dots（L-Cys-CDs）are used as a detection platform,using molecular spectroscopy,mainly molecular fluorescence spectroscopy and resonance Rayleigh scattering spectroscopy,supplemented by ultraviolet-visible absorption spectroscopy Fourier near-infrared spectroscopy,while using XRD,TEM,zeta potential map and other characterization methods to further corroborate,enrich experimental phenomena or further explain the reaction mechanism.An analytical report was established in the experimental report for the rapid detection of curcumin by fluorescence spectroscopy.Sensitive detection of geraniol by resonance Rayleigh scattering spectroscopy.At the same time,two different analysis methods were established by fluorescence spectroscopy and resonance rayleigh scattering spectroscopy.At the same time,Douglasin was detected.After comparison,the more sensitive resonance Rayleigh scattering spectroscopy was used as the detection method.The new method was finally applied to actual samples,and the experimental results were satisfactory.This thesis was completed with the support of the National Natural Science Foundation of China（No.21475014）and the Chongqing Graduate Innovation Project（CYS19356）.The main research contents are as follows:1.Fluorescence resonance energy transfer based on the interaction of L-histidine-functionalized gold nano with curcumin and its analytical applicationIt was found that L-histidine-functionalized gold nanoclusters were significantly quenched with curcumin under the action of curcumin.Based on this,we established a new method for rapid detection of trace curcumin in the environment.In the experiment,L-histidine-functionalized gold nanometer（L-Cys-CDs）was used as a probe reagent,and an appropriate amount of curcumin solution was added to L-Cys-CDs under the optimized condition of pH=7.1.The bright fluorescence of L-Cys-CDs was quenched,and it was found that the quenched fluorescence intensity had a positive correlation with the increase of the amount of curcumin.It has been proved through experiments that the fluorescence intensity quenching degree of L-Cys-CDs and curcumin concentration have a good linear relationship in the range of 5.0×10-7-1.1×10-5mol/L,and the detection limit is 3.1×10-8mol/L.The experiment used water samples and urine samples from healthy volunteers for analysis and application,and found that the recovery rate was between 99.5%and 105.0%,and the results were satisfactory.Further comparison of the literature further illustrates the simplicity and efficiency of the detection method.2.L-histidine-functionalized gold nanoparticles as light scattering probe for rapid detection of natural plant active ingredient DiosmetinGeraniol,as a natural flavonoid,has many excellent chemical properties and good biological activity.In this article,L-histidine was used as a modifier and reducing agent,and gold nanoparticles with fluorescent properties were obtained by simple preparation.In BR buffer solution with a pH of 4.5,the addition of diosmetin significantly increased the light scattering intensity of the system.Based on this,an experimental method for quickly detecting diosmetin was constructed based on the intensity variation of the resonance Rayleigh scattering spectrum.Under optimal experimental conditions,the linear range of L-His-AuNPs for detecting diosmetin was 7.0-140.0×10-88 mol/L,and the detection limit was 1.8×10-88 mol/L.The method was applied to the detection of diosmetin in actual samples,and satisfactory results were obtained.3.Analysis and determination of natural plant active ingredient Taxifolin by L-cysteine-functional carbon quantum dotsIn the experiment,citric acid was used as a carbon source L-cysteine as a modifier,and carbon quantum dots（L-Cys-CDs）with high fluorescence yield were prepared by a simple hydrothermal synthesis method.Experimental analysis found that L-Cys-CDs can be used as a fluorescent probe and a resonance Rayleigh scattering（RRS）probe to detect Taxifolin in the presence of Fe3+.Under the best experimental conditions,Fe3+can significantly quench the fluorescence of carbon quantum dots.When docetaxin was added to the above system,it was found that the fluorescence of the quenching system was restored,and the RRS intensity of the system was significantly enhanced when the three coexisted.Based on this,this article constructs two spectroscopic methods to detect Taxifolin preferentially.Finally,it is determined that RRS spectroscopy with more sensitive detection limit and wider linear range is used as a rapid detection method for Taxifolin.Under the best experimental conditions,the intensity of RRS enhancement has a good linear relationship with the concentration of Taxifolin in the range of 0.9-160×10-7mol/L.The minimum detection limit is 8.6×10-99 mol/L.The correlation coefficient It is0.9975.Moreover,the content of the standard sample detected by this experimental method is compared with the measured value of the high-performance liquid chromatography marked by the seller,and the addition and recovery experiments of water samples have all obtained satisfactory results. |
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