| High performance liquid chromatography(HPLC)is one of the most commonly used methods of separation and analysis.The HPLC instrument structure is relatively simple,cheap,and easy to operate.Because of the excellent separation performance,HPLC can purify or separate most of chemical substances,HPLC is widely used in chemistry,pharmaceuticals,environmental analysis,biomedical analysis,and drug treatment monitoring.Resonant Rayleigh scattering(RRS)refers to the phenomenon that when Rayleigh scattering coincidences or is close to the molecular absorption band of the analyte,the electron will absorb the photon energy due to resonance at the similar frequency and generate new scattering,accompanied by the appearance of new characteristic peak and the significant enhancement of scattering signal.It is sensitive,cheap,simple and quick.RRS has been widely used in the detection of small molecule drugs,proteins,trace metal ions,surfactants,etc.However,RRS has low selectivity and cannot distinguish analytes with similar structures.High performance liquid chromatography combined with resonance Rayleigh scattering(HPLC-RRS)combines the advantages of high selectivity and high separation ability of HPLC for complex samples with the advantages of high sensitivity of RRS.HPLC has become one of the modern detection techniques widely used in food,drug and environmental analysis.Cytokinin(CTK)is a kind of plant hormone that promotes cell growth and differentiation.It has been banned as a food additive in China since 2015.However,due to its excellent sprouting effect,some people still add it to food illegally.Proton pump inhibitor(PPI)is a commonly used gastric drug.Because its overuse will cause a series of side effects,it is necessary to control its blood concentration.Therefore,the thesis studies the application of HPLC-RRS in the detection of CTK and PPI.The main research contents of the thesis are as follows:1.Simultaneous determination of cytokinins by high performance liquid chromatography with resonance Rayleigh scattering and mechanism discussion.Based on Pd(Ⅱ)and erythrin B(erythrin B)as probe,a HPLC-RRS technique was developed for the detection of three CTKs,including 6-benzylaminopurine(BA),kinetin(KT)and zeatin(ZT).In this work,Pd(Ⅱ)is added into the system to form ternary ion association complexes for the first time,which results in lower limit of detection and extends the application of the HPLC-RRS.The experimental conditions were optimized.In order to investigate the reaction mechanism,the ternary ion association complexes were characterized by ultraviolet-visible spectrum(UV-vis),dynamic light scattering(DLS),scanning electron microscopy(SEM)and the calculation of the density functional theory.In a HAc-Na Ac buffer solution(p H 4.10),a ternary complex of cytokinin: Pd(Ⅱ): EryB(1:1:2)was formed.Under the optimal conditions,the RRS intensity and CTK concentration had a good linear relationship in the range of 7.2 × 10-2-25 μg·m L-1.The detection limits of BA,KT and ZT were 0.91,1.5 and 2.3 ng·m L-1,respectively.In addition,the method was applied to the simultaneous detection of cytokinins in real samples.The recovery rate obtained was between 98.12% and 103.2%,and the relative standard deviation(RSD)ranged from 1.7% to 4.2%,indicating that the proposed method can be used for the analysis of CTK in actual samples.2.Simultaneous determination of proton pump inhibitors by high performance liquid chromatography with resonance Rayleigh scattering and mechanism discussion.In the present study,by introducing eosin Y(EY)and Pd(Ⅱ)as probes,HPLC-RRS method was proposed for the detection of PPIs,including Rabeprazole(RPZ),omeprazole(OPZ),pantoprazole(PPZ)and lansoprazole(LPZ).In order to investigate the interaction and the mechanism of signal enhancement,the complexes were characterized by UV-vis,DLS,RRS,SEM and the calculation of the density functional theory(DFT).The results indicated that PPIs,Pd(Ⅱ)and EY formed ionic associations at1:1:2 due to electrostatic attraction,which increased the volume and hydrophobicity of the system,resulting in the enhancement of RRS signals.Under the optimized experimental conditions,a linear relationship was found between RRS intensity and the concentration of PPIs within 2.2 × 10-2-25 μg·m L-1.The limits of detection were 10.1,5.62,7.50 and 8.29 ng·m L-1 for RPZ,OPZ,PPZ and LPZ,respectively.In addition,the established method was validated and applied for the human serum samples.The recovery rate obtained was between 96.50% and 104.5%,and the RSD was between 1.8%and 4.2%,indicating that this method has a broad application prospect in the determination of PPI.3.Resonance Rayleigh scattering for high sensitive detection of penciclovir based on Erythrosine B and Pd(Ⅱ).A RRS method for the detection of penciclovir(PCV)was proposed based on enhancing the volume and hydrophobicity of PCV by introducing EryB and Pd(Ⅱ).The binding sites and the enhancement mechanism of RRS signal were investigated by means of UV-vis,DLS and distribution fraction calculation.In HAC-Na AC buffer(p H 4.7),EryB and Pd(Ⅱ)form binary complex due to electrostatic interaction.When PCV reacted with the binary complex,the RRS intensity enhanced with the increase of PCV.Under the optimal conditions,the RRS intensity and PCV concentration had a good linear relationship in the range of 0.013-3.0 μg·m L-1,the regression coefficient was 0.9988,the LOD was 3.70 ng·m L-1,and the LOQ was 12.2 ng·m L-1.The recovery rate of PCV in actual waste water samples and human plasma samples was between 97.2% and 102%,and RSD was in the range of 2.2 to 4.8%.The obtained results showed that the proposed method can be used for the analysis of PCV in actual samples. |
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