Fluorescence PET (photo-induced electron transfer) sensor for water based on anthracene-amino acid

An anthracene-amino acid system with two carboxyl groups has been designed and synthesized as a new class of fluorescence PET (photo-induced electron transfer) sensor for detection of water in organic solvents. An enhancement in fluorescence is observed with increasing water content in 1,4-dioxane, THF, acetonitrile and ethanol, which is attributable to the suppression of PET by the intramolecular proton transfer of the carboxyl proton to the amino group. The detection limit and quantitation limit are, respectively, 0.1 and 0.3 wt% for 1,4-dioxane, 0.4 and 1.2 wt% for THF, 0.1 and 0.3 wt% for acetonitrile and 0.1 and 0.3 wt% for ethanol.