[Fluorescence spectra of Bletilla striata aqueous extraction]

Three-dimensional fluorescence spectrum and ultraviolet absorption spectrum of Bletilla striata extraction drawn by boiling water were reported. Three fluorescence peaks, located at lambda(ex)/lambda(em) = 227/299 nm, 271/299 nm and 258/ 389 nm respectively, were observed in the three-dimensional fluorescence spectrum. Among them, the two former peaks having the same emission wavelengths were produced by one fluorescent component, while the latter peak was produced by another. Three-dimensional fluorescence spectrum is a characteristic mark of Bletilla striata, therefore it can be used in qualitative identification. The distance between emission wavelengths of the two components was 90 nm, so the fluorescence intensity of two components could be measured separately without pre-separation. For dilute solutions of Bletilla striata aqueous extraction, good linear relationships between fluorescence intensity and concentration of two components were obtained, thereby the quantitative determination of the two components may be carried out. In the range of pH 1.5 to pH 12.5, the fluorescence intensity of the two components changes with the increase in pH, indicating dissociable protons exist in the molecular structure of the two components.