A rhodamine derivative probe for highly selective detection of Cu(II)

Background: Abnormal Cu(II) ions levels may affect many biological functions, and it is of great importance to detect Cu(II) ions in organisms. Methods: Herein, we report a near-infrared (NIR) fluorescent probe EtRh-N-NH2 for the detection of Cu(II). In the probe structure, a rhodamine core was used, and a hydrazine group was employed as the responsive site. Results & Conlusions: EtRh-N-NH2 displayed sensitive, specific and fast response upon Cu(II) with excellent linear relationship between the concentration and fluorescence emission intensity in 0-1 mu M range. The releasing EtRh-COOH exhibited 762 nm of emission wavelength with a 75 nm of Stokes shift.