Rhodamine based turn-ON dual sensor for Fe3+ and Cu2+

A new rhodamine-based dual sensor selectively detects Cu2+ and Fe3+. Complexation with Fe3+ triggers the formation of a highly fluorescent ring-open form, while Cu2+ forms a nonfluorescent complex detectable by its UV-vis spectrum. Both Cu2+ and Fe3+ give an immediate color change and the sensing mechanism is reversible, as indicated by disappearance of the color with the addition of excess EDTA. (C) 2011 Elsevier Ltd. All rights reserved.