Construction of FRET-based CDs@RBH Ratiometric Fluorescent Probe for Cu²⁺ Sensing

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Elevated copper ion (Cu²⁺) concentrations present significant risks to human health and ecological balance.
• Sensitive and selective detection methods are crucial for monitoring Cu²⁺ in various environments.

Purpose of the Study:

• To develop a novel ratiometric fluorescent probe for the sensitive and selective detection of Cu²⁺.
• To utilize fluorescence resonance energy transfer (FRET) for dual-signal readout in Cu²⁺ detection.

Main Methods:

• Fabrication of a ratiometric fluorescent probe (CDs@RBH) using carbon quantum dots (CDs) as energy donor and rhodamine hydrazide (RBH) as acceptor via electrostatic assembly.
• Investigating the FRET mechanism triggered by Cu²⁺-induced opening of the RBH spirolactam ring.
• Analyzing the dual-signal response: decrease in CDs fluorescence and increase in RBH-Cu²⁺ complex emission.

Main Results:

• The probe demonstrated high selectivity and sensitivity for Cu²⁺ detection, with a limit of detection (LOD) of 0.65 μM and a limit of quantification (LOQ) of 2.09 μM.
• Successful application in tap water samples with excellent recovery rates (96-108%).
• The probe exhibits environmental stability and dual-channel signal verification.

Conclusions:

• The developed CDs@RBH probe offers a straightforward synthesis, robust performance, and reliable dual-signal detection for Cu²⁺.
• This ratiometric fluorescent probe is a promising tool for real-world monitoring of Cu²⁺ in environmental and biological systems.