Upconversion nanosensor for sensitive fluorescence detection of Sudan I-IV based on inner filter effect

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Food Safety

Background:

• Sudan dyes are carcinogenic food additives, necessitating sensitive detection methods.
• Existing detection methods may lack the required sensitivity or specificity.
• The carcinogenicity of Sudan dye metabolites poses a significant risk to human health.

Purpose of the Study:

• To develop a novel nanosensor for the sensitive and selective detection of Sudan dyes (Sudan I-IV).
• To utilize fluorescence quenching of upconversion nanoparticles (UCNPs) for Sudan dye quantification.
• To validate the nanosensor's performance in real-world food samples.

Main Methods:

• Fabrication of hexadecyl trimethyl ammonium bromide (CTAB) stabilized upconversion nanoparticles (UCNPs).
• Utilizing the inner filter effect (IFE) for fluorescence quenching of UCNPs by Sudan dyes.
• Optimizing detection conditions and determining the limit of detection (LOD) for Sudan I-IV.
• Assessing the nanosensor's selectivity and applying it to chili powder samples.

Main Results:

• The nanosensor demonstrated effective fluorescence quenching of UCNPs in the presence of Sudan I-IV.
• Linear detection ranges were established for Sudan I-IV from 0.01-40 μg/mL.
• Limits of detection (LOD) were as low as 2.83 ng/mL for Sudan II.
• The nanosensor showed good selectivity and was successfully applied to detect Sudan dyes in chili powder.

Conclusions:

• A novel CTAB-stabilized UCNP-based nanosensor was successfully developed for sensitive Sudan dye detection.
• The inner filter effect provides an effective mechanism for fluorescence quenching by Sudan dyes.
• The developed nanosensor is a promising tool for ensuring food safety by detecting banned Sudan dyes in food products.