An Ultrasensitive Fluorescence Sensor with Simple Operation for Cu²⁺ Specific Detection in Drinking Water

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Biomedical Sensing

Background:

• Copper ion (Cu²⁺) overexposure poses significant health risks.
• The nonbiodegradable nature of copper necessitates sensitive detection methods.
• Existing detection methods may lack sensitivity or specificity.

Purpose of the Study:

• To develop a novel, highly sensitive, and specific fluorescent detection strategy for copper ions (Cu²⁺).
• To establish an enzyme-free and label-free sensing system for practical copper ion detection.

Main Methods:

• Utilized the peroxidase-like catalytic activity of Cu²⁺.
• Employed Amplex Red as a nonfluorescent substrate, oxidized to fluorescent resofurin by Cu²⁺ with H₂O₂.
• Optimized hydrogen peroxide (H₂O₂) concentration and incubation time for sensitivity and reproducibility.

Main Results:

• A "turn-on" fluorescent signal was achieved for Cu²⁺ detection.
• The developed assay demonstrated excellent specificity for copper ions.
• Achieved a low limit of detection (LOD) of 1.0 nM for Cu²⁺.
• Successfully detected Cu²⁺ in real water samples (tap and purified bottled water) with good recovery.

Conclusions:

• The developed fluorescent strategy provides a sensitive and specific method for copper ion detection.
• The enzyme-free, label-free system is simple to operate and applicable to environmental water samples.
• This method holds promise for monitoring copper ion levels in various settings to mitigate health risks.