3D excitation-emission matrix fluorescence spectroscopy of Biluochun before and after Tomb-Sweeping Day

Abstract

<p class="Abstract">Tea is an important public drink and its value is in accordance with the time of picking, for example, tea picked before Tomb-Sweeping Day is more expensive than that after Tomb-Sweeping Day. To avoid buying shoddy tea, it is necessary to identify the picking time of the tea. Considering the fact that the chemical components are related to the picking time, in this work, fluorescence spectroscopy is proposed to find the difference between these two kinds of Biluochun. The intensity of the excitation and emission wavelengths for the Biluochun was measured at the same to obtain 3D fluorescence spectra. The contour maps of Biluochun picked before and after Tomb-Sweeping Day were drawn and compared. The results shown that fluorescent intensity at the region from 660 nm to 680 nm, which is corresponding to chlorophyll, is obviously different for both kinds. The different fluorescent intensity demonstrated that the chlorophyll contained in Biluochun after Tomb-Sweeping Day was higher than that before Tomb-Sweeping Day, which can be used to classify these two kinds.</p>