A Technique for Sensing Organic Compounds Using Fluorescence Maximum Shift In Laser Dyes

Abstract

A technique that could be used for sensing organic compounds is presented. In ethanol, Rhodamine-6G (a laser dye) was dissolved to obtain a Rhodamine-ethanol (Rh-Eth) solution with the concentration of Rhodamine-6G being 0.005 M. Methanol (0.25 cm3) was added to the Rh-Eth solution and the Rh-Eth-Me solution so obtained was pumped with a nitrogen laser. A blue shift in the fluorescence spectrum of the Rh-Eth-Me was observed as compared to the Rh-Eth solution without methanol. A similar blue shift was observed in the Rh-Eth solution when acetone and acetonitrile were separately added. When Rhodamine-6G and Coumarin460 were added with Polymethyl methacrylate (PMMA) in ethanol, a blue shift was observed in the fluorescence spectrum as compared to the Rh-6G and Cou460 in ethanol without PMMA. The phenomena of spectral shifts in the fluorescence spectrum can be used to sense organic compounds and a mechanism is discussed.