Analysis Of Kaempferol And Gallic Acid In Chinese Medicine By Sensitized Fluorescence

Kaempferol is an active component of Chinese herbal medicine Carthami flos (Honghua in Chinese). Gallic acid is an active component of Chinese herbal medicines Rosae rugosae flos (Meiguihua in Chinese), Granatum (Shiliupi in Chinese) and Rosae chinensis flos (Yuejihua in Chinese). Fluorescence properties of kaempferol and gallic acid were studied in this thesis, and fluorescent method and thin-layer scanning method were proposed for the determination of kaempferol and gallic acid in Chinese herbal medicines.Two parts were included in this thesis:1. Fluorescence properties of kaempferol were studied. It was found that kaempferol is basically no fluorescence. But when aluminum ion or borax was added into kaempferol solution, sensitized fluorescence was observed. Especially, aluminum ion can give a best sensitization effect. Influence of experimental conditions on fluorescence sensitization was studied. The suitable acidity was found to be pH3.6~4.4. Using quinine sulfate as a reference, fluorescence quantum yield of the Al(III)-kaempferol system was measured to be 0.038. Based on this fluorescence reaction, a fluorescent method was established for the determination of kaempferol in Honghua, and the content of kaempferol in a Honghua sample was determined to be 0.0559%. For verifying the accuracy of the fluorescent method, a thin-layer fluorescence scanning method was proposed. This method was done by firstly separate the components of Honghua via thin-layer chromatography, and secondly spray aluminum ion on thin layer plate to enable kaempferol to produce fluorescence, and then measure fluorescence intensity of the spots by fluorescence scanning. Using this method, content of kaempferol in the Honghua sample was measured to be 0.0541%, which was basically the same as that of the solution fluorescent method.2. Fluorescence properties and analyzing method of gallic acid were studied. It was found that the fluorescence of gallic acid is very weak. Addition of borax into gallic acid solution can give a fluorescence enhancement, and further addition of sodium dodecyl sulfate (SDS) into the system can make the fluorescence stronger and steady. Therefore, borax and SDS was used together as fluorescence enhancement reagents. Based on this ternary fluorescence system, a fluorescent method was established to analysis the content of gallic acid in Chinese herbal medicines, and the contents of gallic acid in Meiguihua, Shiliupi and Yuejihua were determined to be 0.537%, 0.348% and 0.336%, respectively. For confirming the reliability of the method, a thin-layer absorbance scanning method was proposed for the determination of gallic acid in Chinese herbal medicines, and the results obtained were basically the same as that of the fluorescent method.