A ratiometric fluorescent sensor for Al³⁺ and Cu²⁺ detection in food samples

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Aluminum (Al³⁺) and copper (Cu²⁺) are common in food but pose risks at excessive levels.
• Current detection methods lack speed, sensitivity, or portability for effective food safety control.
• Need for advanced technologies to monitor hazardous metal ion concentrations in food products.

Purpose of the Study:

• To develop a fast, sensitive, and portable ratiometric fluorescent sensor.
• To detect hazardous levels of aluminum (Al³⁺) and copper (Cu²⁺) in food samples.
• To utilize gold nanoclusters (G-AuNCs) and nitrogen-doped graphene quantum dots (N-GQDs) for metal ion sensing.

Main Methods:

• Synthesized GSH-stabilized gold nanoclusters (G-AuNCs) and N-doped graphene quantum dots (N-GQDs) via hydrothermal method.
• Constructed a GQDs@AuNCs ratiometric fluorescent sensor using electrostatic interactions.
• Employed fluorescence intensity changes of G-AuNCs and N-GQDs for quantitative analysis of Al³⁺ and Cu²⁺.

Main Results:

• Al³⁺ increased G-AuNCs fluorescence, while Cu²⁺ quenched it; N-GQDs fluorescence remained stable.
• A strong linear correlation was observed between the fluorescence ratio and ion concentrations (Al³⁺: 0.5-500 μM, Cu²⁺: 1-200 μM).
• Achieved low limits of detection (LOD) of 0.66 μM for Al³⁺ and 0.44 μM for Cu²⁺.

Conclusions:

• The developed fluorescent sensor offers simple synthesis and rapid, highly sensitive detection capabilities.
• The sensor is suitable for detecting Al³⁺ and Cu²⁺ in real food samples like fried dough twists and shellfish.
• This technology provides a promising tool for ensuring food safety and preventing heavy metal contamination.