Determination of sunset yellow in soft drinks based on fluorescence quenching of carbon dots

• The CDs were prepared in air and not only highly soluble in water but also uniform in size
• A rapid assay of sunset yellow was performed and fluorescence resonance energy transfer process was proved.
• A method was designed for sunset yellow from 0.3 to 8.0 μmol L-1, with a detection limit (3 σ/k) of 79.6 nmol L-1.

Fluorescent carbon dots was prepared by heating N-(2-hydroxyethyl)ethylene diaminetriacetic acid in air. The carbon dots were not only highly soluble in water but also uniform in size, and possessed strong blue fluorescence and excitation wavelength-dependent emission properties with the maximum excitation and emission wavelength at 366 nm and 423 nm, respectively. Food colorant sunset yellow whose excitation and emission wavelength at 303 nm and 430 nm could selectively quench the fluorescence of carbon dots, efficient fluorescent resonance energy transfer between the carbon dots and sunset yellow is achieved. This was exploited to design a method for the determination of sunset yellow in the concentration range from 0.3 to 8.0 μmol L− 1, with a limit of detection (3 σ/k) of 79.6 nmol L− 1. Furthermore the fluorimetric detection method was established and validated for sunset yellow in soft drinks samples with satisfactory results.

Graphic abstractCarbon dots with fluorescence properties were prepared and used to sunset yellow determination.Figure optionsDownload as PowerPoint slide