Fast detection of melamine using silver nanoparticles capped with l-cysteine functionalized carbon dots

Area of Science:

• Analytical Chemistry
• Materials Science
• Food Safety

Background:

• Melamine is fraudulently added to food, especially dairy, to artificially increase nitrogen content.
• Past incidents of melamine contamination have caused significant health issues in humans and animals.
• There is a critical need for rapid, reliable methods to detect melamine in food products.

Purpose of the Study:

• To develop a fast, simple, reliable, and efficient method for detecting melamine.
• To create a sensor based on silver nanoparticles capped with l-cysteine functionalized carbon dots (cCDs/AgNPs).

Main Methods:

• Synthesis of silver nanoparticles capped with l-cysteine functionalized carbon dots (cCDs/AgNPs).
• Colorimetric detection of melamine by observing color change of cCDs/AgNPs solution upon heating.
• Quantitative analysis using ultraviolet-visible spectroscopy.

Main Results:

• The cCDs/AgNPs solution exhibited a distinct color change from yellow to pink and blue within two minutes in the presence of melamine.
• The method demonstrated high sensitivity, detecting melamine at concentrations as low as 0.1 μg mL⁻¹.
• Ultraviolet-visible spectroscopy showed good linearity for melamine detection in the range of 0.5–4.5 μg mL⁻¹, with a detection limit of 0.03 μg mL⁻¹.
• The method was successfully validated for melamine detection in a milk matrix.

Conclusions:

• The developed cCDs/AgNPs sensor provides a sensitive and rapid method for melamine detection.
• This approach is suitable for real-time food monitoring, particularly in dairy products, to ensure melamine-free food.
• The method contributes to enhancing food safety and protecting public health from melamine contamination.