A new fluorescent probe of rhodamine B derivative for the detection of copper ion

A new fluorescent probe, rhodamine B hydrazide oxalamide (RBHO), which shows very weak fluorescence, was synthesized, and its fluorescence could be substantially enhanced by the addition of copper ion. The probe shows a high selectivity and sensitivity to copper ion by forming a 1: 1 complex in acetonitrile, and the chelating is reversible. Limit of detection for copper ion in acetonitrile was found to be 3.7 x 10(-8) mol L-1. It was also found that copper ion could catalyze the hydrolysis of the probe in 50% (v/v) buffered (10 mM Tris-HCl, pH 7.0) water/acetonitrile giving a highly fluorescent product, and the fluorescence detection of copper ion was developed in this neutral buffered media with a detection limit of 6.4 x 10(-7) mol L(-)1. Determination of copper ion in water and synthetic samples in the presence of different interfering metal ions was successfully carried out with the new probe RBHO. (C) 2007 Elsevier B.V. All rights reserved.