A new method for Eosin preparation and examination of its absorption and emission spectra

Eosin is one of the original dyes of xanthenes derivatives. It is also one of the main derivatives of fluorescein and has brilliant fluorescence. Eosin disodium salt called "Eosin Y" is the most useful form of this compound. In common procedures, eosin is usually obtained by the action of bromine on fluorescein, which has not good yield and purity degree. In this research, it is prepared by the reaction  of /on fluorescein in acidic water-acetone mixture. It has been tried to find optimum conditions, which allow the precipitation of eosin while the other brominated derivatives of fluorescein remain soluble. Elemental analysis, UV-Vis spectrophotometry and FTIR spectrometry are applied to confirm the results of the new method. The absorption and emission spectra have been obtained with using a spectrofluorometer. The total luminescence spectrum is demonstrated as a three-dimensional plot to show tile intensity of file luminescence signal at different wavelength. The results show good agreements with references.