Study On Fluorescent Properties And Analytical Methods Of Quinine Alkaloids

Fluorescent properties of4kinds of quinine alkaloids, including quinidine, cinchonine,cinchonidine and hydroquinine, were studied. Relationship between fluorescence andmolecular structure was discussed. A new thin layer chromatography-fluorescence scanningmethod was proposed for the determination of quinine and cinchonine in herbal medicinePerucian bark (Jinjinashupi) was proposed.Two parts were included in this thesis:1. Absorption and fluorescence spectra of4kinds of quinine alkaloids were studied.Influences of experimental conditions (pH, ionic strength, and solvent) on spectral propertywere tested. The excitation wavelengths of the quinine alkaloids were located at225nm-350nm, presenting3fluorescence excitation peaks. The fluorescence emission wavelength λemand fluorescence intensity varied along with the variation of pH. In the pH range of1.0~3.0,the λemlocated at419~445nm; while in the pH range of6.0～9.0, λemblue-shifted to about380nm. Using quinine sulfate as a reference, fluorescence quantum yield of quinidine insolution with pH2.0was measured to be0.021; quantum yield of cinchonine in solution withpH8.55was measured to be0.059; quantum yield of cinchonidine in solution with pH2.0was measured to be0.027; quantum yield of hydroquinine in solution with pH2.0wasmeasured to be0.55.2. Three dimensional fluorescence spectra of Perucian bark extracting solution werestudied. It was found that multi fluorescent components were contained and their fluorescencespectra were overlapped. Therefore, the contents of them can not be measured directly byfluorimetric method. Fluorescent properties of quinine alkaloids on silica gel plate werestudied, and a thin layer chromatography-fluorescence scanning method was proposed for thedetermination of quinine and cinchonine in Perucian bark, the results were4.45%and6.94%,respectively.