Visualized electrochemiluminescence detection of trace copper in practical food samples

Area of Science:

• Analytical Chemistry
• Food Science
• Nanotechnology

Background:

• Copper contamination poses a significant threat to food safety within the food supply chain.
• Accurate and rapid detection methods for trace copper ions (Cu²⁺) are crucial for monitoring food quality.

Purpose of the Study:

• To develop a quick, visible, and highly sensitive method for quantifying trace copper ions in food samples.
• To assess the applicability of the developed method for real-world food safety analysis.

Main Methods:

• Conjugation of polymer dots (Pdots) with a copper-specific DNA aptamer.
• Functionalization of Pdots with rhodamine B (RhB) to quench electrochemiluminescence (ECL) via resonance energy transfer.
• Detection of Cu²⁺ through the restoration of ECL signal upon selective RhB release.

Main Results:

• The method demonstrated remarkable linearity between the ECL signal and the logarithm of Cu²⁺ concentration (1 ng/L to 10 μg/L).
• Achieved an impressively low limit of detection of 11.8 pg/L for trace copper ions.
• Successfully visualized and quantified trace Cu²⁺ (∼0.2 μg/g) in practical Glycyrrhiza uralensis Fisch. samples.

Conclusions:

• The developed Pdots-based method offers a sensitive and visual approach for trace copper detection in food.
• This technique holds significant potential for early prevention of copper contamination in the food supply chain.
• The method's applicability to real food samples highlights its practical value for ensuring food safety.