Nitrogen laser induced fluorescence in laser dyes for sensing of organic compounds

A laser dye Coumarin460 was dissolved in ethanol at a concentration of 0.01 M.When the dissolved dye was added with 0.25 cm3 methanol and was pumped with nitrogen laser, the fluorescence spectrum showed a red shift, in comparison without methanol. The red shift was also observed when the dye solution was added with acetone and acetonitrile. On the other hand, when the dye solution was exposed to fumes of Heena (Lawsonia alba), Khus (Vitis zizgnoides) and Rose water, a blue shift was observed in its fluorescence spectrum. The spectral shifts observed indicated that the technique could be used successfully for detecting organic compounds. A mechanism is discussed for understanding the observed changes in fluorescence spectra.