A novel turn-on fluorescent strategy for sensing ascorbic acid using graphene quantum dots as fluorescent probe

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Ascorbic acid (AA) is a vital antioxidant with crucial biological roles.
• Accurate quantification of AA is essential for health monitoring and diagnostics.
• Existing detection methods may lack sensitivity, speed, or applicability to complex matrices.

Purpose of the Study:

• To develop a facile and rapid fluorescence turn-on assay for the detection of ascorbic acid (AA).
• To utilize orange-emitting graphene quantum dots (GQDs) as a fluorescent probe.
• To establish a sensitive method for AA determination in biological samples like human serum.

Main Methods:

• Development of a fluorescence assay based on graphene quantum dots (GQDs).
• Utilizing the quenching effect of o-benzoquinone, derived from catechol oxidation, on GQD fluorescence.
• Employing horse radish peroxidase (HRP) and hydrogen peroxide (H2O2) in the reaction system.
• Demonstrating fluorescence recovery in the presence of ascorbic acid (AA) due to its radical scavenging activity.

Main Results:

• The assay exhibited a linear correlation between fluorescence intensity and H2O2 concentration (3.33–500µM, LOD 1.2µM).
• Linear detection of AA was achieved in the range of 1.11–300µM with a low detection limit of 0.32µM.
• The method demonstrated successful application for AA determination in human serum samples with satisfactory accuracy.

Conclusions:

• A novel, rapid, and sensitive fluorescence turn-on assay for ascorbic acid (AA) detection was successfully developed.
• The assay leverages the unique properties of graphene quantum dots (GQDs) and their interaction with reactive oxygen species.
• The proposed method shows significant potential for practical applications in clinical diagnostics and biological sample analysis.