Fluorometric Analysis Of Chinese Medicine Xiangru And Zushima

Fluorescent properties of active components of Xiangru (Moslae herba) and Zushima (Girald daphne bark) were studied in this thesis. Influences of experimental conditions on fluorescence spectra were investigated. According to the similarity of fluorescence properties of thymol and carvacrol, a fluorimetric method for the determination of total amount of them in Xiangru was proposed, and its reliability was verified by a thin-layer light absorption scanning method. Fluorescence sensitization reaction of daphnetin was studied, and a thin-layer scanning method for the determination of daphnetin in Zushima was established.Four parts were included in this thesis:1. Fluorescence spectra of thymol and carvacrol were studied. The influence of acidity, surfactant and solvent effects on spectral properties, and the linear relationship between fluorescence intensity and concentration were investigated. Using a pH-fluorescence method, the ionization constant of thymol was measured to be pKa=10.57, and carvacrol was pKa=10.41. A pH-absorption method was also employed to measure the ionization constants, and the results were essentially the same as that of pH-fluorescence method.2. Fluorescent property of Xiangru methanol extraction was studied, and it is similar with that of thymol and carvacrol. Based on this fact, a fluorimetric method for determination of total amount of thymol and carvacrol in Xiangru crude drugs was proposed, and the analyzed result for a Xiangru control materials was 0.52%. A thin-layer light absorption scanning method was employed to analyze the same Xiangru sample, and the obtained result was 0.49%, essentially coincident with that of fluorimetric method.3. Intrinsic and sensitized fluorescence of daphnetin was studied. The fluorescence of daphnetin was very weak, fluorescence quantum yield was measured to be 0.008, using quinine sulfate as a reference. Stronger and steady fluorescence can be obtained when adding borax and cetyltrimethyl ammonium bromide (CTAB) into daphnetin solution, fluorescence quantum yield of the system increased to 0.020.4. Fluorescence spectra of Zushima crude drugs were studied, and several components with strong fluorescence were observed, therefore the amount of daphnetin in Zushima can not be determined directly by fluorimetric method. A thin-layer scanning method was developed to analyze daphnetin in Zushima, and a Zushima control materials was analyzed using this method, the result was 0.51%.