Analytical Sciences

Label-free, Water-soluble Fluorescent Peptide Probe for a Sensitive and Selective Determination of Copper Ions

Tao YANG,*,** Fang ZHU,*,** Tianxiao ZHOU,*,** Jianzhong CAO,*,** Yibo XIE,*,** Meiyi ZHANG,*,** Yan WANG,*,** Dong-Sheng CAO,*** Qinlu LIN,*,** and Lin ZHANG*,**

*National Engineering Laboratory for Rice and By-products Further Processing, Central South University of Forestry and Technology, Changsha 410004, People’s Republic of China
**Department of Food Science and Technology, Central South University of Forestry and Technology, Changsha 410004, People’s Republic of China
***School of Pharmaceutical Sciences, Central South University, Changsha 410083, People’s Republic of China

This study aimed to develop a label-free, sensitive, selective, and environment-friendly fluorescent peptide probe His-His-Trp-His (HHWH) for determining the concentration of copper ion (Cu²⁺) in aqueous solutions. The results demonstrated that the designed HHWH has a high selectivity and sensitivity for monitoring the concentration of free Cu²⁺ via quenching of the probe fluorescence upon a binding of Cu²⁺. The fluorescence intensity of the HHWH had a linear relationship with the concentration of Cu²⁺ between 10 nM and 10 μM, and the detection limit was 8 nM. Furthermore, HHWH could be regenerated with sulfide ions at least five times. The concentrations of Cu²⁺ in three different real water samples were detected using this probe, and the results were consistent with the one detected using an atomic absorption spectrometer. Thus, HHWH can be used as an accurate and feasible fluorescent peptide probe for detecting Cu²⁺ in aqueous solutions.

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