Trace Detection of Erythrosine B in Sugar

Significance of the Topic

Erythrosine B is a synthetic red dye widely used in foods, pharmaceuticals, and cosmetics. Despite regulatory approval at low levels, rodent studies link its ingestion to thyroid tumor formation and potential behavioral effects in children. The World Health Organization recommends a daily intake below 0.1 mg/kg body weight. Reliable, on-site monitoring methods are essential to ensure consumer safety and regulatory compliance.

Objectives and Overview of the Study

This study evaluates the Metrohm Instant SERS Analyzer (Misa) for rapid, trace-level detection of erythrosine B in sugar matrices. Both laboratory-spiked and commercial colored sugar samples were analyzed to demonstrate sensitivity, selectivity, and applicability in field screening scenarios.

Methodology and Instrumentation

A simple extraction protocol was implemented whereby sugar samples spiked with erythrosine B were dissolved in ethanol, incubated for five minutes, then combined with gold nanoparticle colloid and a NaCl solution to enhance SERS response. The sample mixture was measured using the portable Misa system, leveraging Metrohm’s Orbital-Raster-Scan (ORS) technology for high-quality spectral acquisition.

• Instrumentation Used
  • MISA Advanced Analyzer: portable SERS platform with ORS spectrograph, Bluetooth/USB connectivity, and vial attachments.
  • ID Kit – Au NP: gold colloidal solution, disposable pipettes, sample vials, and spatula for nanoparticle mixing.
• Operational Parameters
  • Laser power: 5 mW
  • Integration time: 1 s
  • Averages: 10
  • Raster scan: ON

Key Results and Discussion

The method achieved clear detection of erythrosine B at concentrations down to 10 µg/g in sugar. Library matching of SERS spectra confirmed the dye’s presence in commercial pink decorating sugar, with minor peak shifts observed but not affecting identification. Total analysis time—including sample preparation and measurement—was under five minutes, demonstrating robustness and reproducibility.

Benefits and Practical Applications

• Minimal sample preparation and low consumable requirements.
• Portable, battery-powered system suitable for on-site and mobile laboratory use.
• Cost-effective alternative to traditional methods such as HPLC or CE.
• Rapid turnaround supporting real-time food safety surveillance.
• Adaptability across diverse testing environments, from high-resource labs to field operations.

Future Trends and Opportunities

• Expansion of spectral libraries to include additional food additives and contaminants.
• Integration with digital platforms and AI-driven spectral matching for automated analysis.
• Development of multiplex SERS assays for simultaneous detection of multiple analytes.
• Advancements in nanoparticle substrates to further improve sensitivity and reproducibility.

Conclusion

The Misa SERS-based assay provides a sensitive, selective, and rapid approach for detecting erythrosine B in sugar products. Its portability, ease of use, and cost efficiency make it an ideal tool for routine on-site surveillance, enhancing food safety monitoring and regulatory enforcement.