Study On Fluorescent Properties And Analytical Methods Of Several Phenolic Acids

Fluorescence and absorption spectra of active components of Chinese herbal medicine,Salvianolic acid A(SAA), Salvianolic acid B (SAB), Tannin, Resveratrol and Polydatin, arestudied in this thesis. The influence of environmental conditions on fluorescence spectra arealso investigated. The contents of the fluorescence components in Chinese herbal medicineSalvia or Polygonum are determined by thin-layer fluorescence scanning method andthin-layer absorption scanning method.Three parts are included in this thesis:1. Spectral properties of SAA and SAB, active components of Chinese herbal medicineSalvia(Danshen), are studied. The native fluorescence of the two are very week. In boraxbuffer with pH10.5and9.6, SAA and SAB can react with cetyl trimethyl ammoniumbromide (CTAB) to form a fluorescence compounds, resulted in a fluorescence strengthen.The fluorescence excitation and emission wavelengths of the SAA-borax-CTAB complex are375nm and480nm, respectively. The fluorescence excitation and emission wavelengths of theSAB-borax-CTAB complex are391nm and492nm, with fluorescence quantum yield of0.039.Using a thin-layer fluorescence scanning method, the content of SAB in Danshen sample isdetermined to be2.45%.2. Spectral properties of Resveratrol and Polydatin, active components of Chinese herbalmedicine polygonum(Huzhang) are studied. The influence of acidity, organic solvent onintrinsic fuorescence are investigated. The fluorescence excitation and emission wavelengthsof Resveratrol are391nm and492nm, respectively. Using quinine bisulphate as a reference,fluorescence quantum yield of Resveratrol is measured to be0.13. The fluorescence excitationand emission wavelengths of the Polydatin in water and alkaline solution are λex/λem=305/385nm and λex/λem=343/454nm, respectively. The average content of Polydatin inHuzhang sample is determined to be1.75%and1.64%by a thin-layer fluorescence scanningmethod and a thin-layer absorption scanning method, respectively.3. Fluorescence property of Tannic acid is studied. It is found that the native fluorescenceof Tannic acid is very week, but the fluorescence can be sensitized by addition of borax. Thefluorescence excitation and emission wavelengths of the Tannic acid-borax complex are273nm and360nm, respectively. Fluorescence quantum yield of the complex is measured tobe0.0087, using L-tryptophan as a reference.