A rapid and naked-eye visible rhodamine 6G-based chemosensor for sensitive detection of copper(II) ions in aqueous solution

A new rhodamine 6G derivative (R6GHP) has been synthesized for quick recognition of copper(II) ions (Cu2+) in aqueous solutions. The structure of R6GHP has been characterized by nuclear magnetic resonance and electrospray ionization mass spectrometry. Upon binding of Cu2+, the fluorescence intensity remarkably increases with about 36-fold enhancement. In addition, the color change from colorless to pink is visible to the naked eye. In optimal conditions, the fluorescence intensity and absorbance of R6GHP show good linearity with concentration of Cu2+ in the ranges of 1.0 × 10−6 to 1.0 × 10−5 mol L−1 and 1.0 × 10−6 to 1.2 × 10−5 mol L−1, respectively, with detection limits of 3.9 × 10−7 mol L−1 and 1.0 × 10−6 mol L−1. Besides, it has been successfully applied to detect Cu2+ in two water samples.