Synthesis of Fluorescent Carbon Dots and Their Application in Ascorbic Acid Detection

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Fluorescent carbon dots (CDs) are nanomaterials with unique optical properties.
• Developing sensitive and selective methods for active molecule determination is crucial in food analysis.

Purpose of the Study:

• To synthesize water-soluble fluorescent carbon dots (CDs) via a hydrothermal method.
• To develop a CDs/Fe³⁺ composite for the sensitive determination of ascorbic acid.
• To explore the feasibility of macroscopic preparation and application of CDs.

Main Methods:

• Hydrothermal synthesis of CDs using citric acid and ethylenediamine.
• Preparation of a CDs/Fe³⁺ composite.
• Characterization of optical properties, pH dependence, and stability.
• Utilizing fluorescence quenching and recovery for quantitative ascorbic acid analysis.

Main Results:

• Macroscopic preparation of water-soluble fluorescent CDs was feasible.
• The CDs/Fe³⁺ composite demonstrated specific recognition of ascorbic acid.
• An excellent linear relationship was observed for ascorbic acid determination in the range of 5.0-350.0 μmol·L^-1.
• A low detection limit of 3.11 μmol·L^-1 was achieved.
• The method showed satisfactory results for ascorbic acid determination in jujube fruit.

Conclusions:

• The synthesized fluorescent carbon dots composites are suitable for macroscopic preparation.
• The CDs/Fe³⁺ composite offers a rapid, sensitive, and selective method for ascorbic acid determination.
• This approach has broad application prospects in food processing for trace analysis of ascorbic acid.