Discrimination between nanocurcumin and free curcumin using graphene quantum dots as a selective fluorescence probe

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Materials Science

Background:

• Curcumin, a compound with significant nutraceutical value, requires reliable analytical methods for quantification in food products.
• Graphene quantum dots (GQDs) offer unique photoluminescent properties suitable for sensitive detection applications.

Purpose of the Study:

• To develop and validate a graphene quantum dot (GQD)-based nanoprobe for detecting and discriminating between free curcumin and nanocurcumin.
• To assess the applicability of the GQD nanoprobe in real-world nutraceutical formulations.

Main Methods:

• Utilizing the photoluminescent quenching effect of GQDs upon interaction with curcumin species.
• Analyzing spectral shifts (wavelength and intensity) of GQD emission in response to varying curcumin concentrations.
• Quantifying free curcumin and nanocurcumin using their distinct interactions with GQDs.

Main Results:

• GQD photoluminescence exhibited concentration-dependent quenching and red-shifting with free curcumin (458 to 490 nm).
• Nanocurcumin induced only a quenching effect on GQD photoluminescence (458 nm).
• Detection limits were 0.3 μg mL⁻¹ for curcumin and 0.1 μg mL⁻¹ for nanocurcumin.

Conclusions:

• The GQD nanoprobe effectively quantifies and discriminates between free and encapsulated curcumin.
• The method is applicable to complex nutraceutical formulations like functional food capsules and beverages.
• This offers a sensitive and selective analytical tool for curcumin in the food industry.