Fluorescent Peptide Sensor for Detection of Copper Ions

A fluorescent sensor for copper (II) ions was developed based on the quenching of rhodamine B-labeled peptide by copper (II). The sensing mechanism was studied using resonance light scattering, UV-Vis absorption spectroscopy, fluorescence lifetime, and circular dichroism. The results showed that copper (II) might induced the conformational change of the peptide that make rhodamine B approach each other, resulting in the aggregation-caused quenching effect of copper(II) and the rhodamine B-labeled peptide. Moreover, the experimental results displayed that the sensor possessed both linear ranges of 5x10(-4)-1x10(-2) mu mol/L and 0.1-7 mu mol/L with a detection limit of 0.29 nmol/L. The sensor also had a high selectivity for copper(II), and can be successfully employed for the detection of copper(II) ions in lake water samples.