Trace Detection of Erythrosine B in Sugar

Significance of the Topic

Erythrosine B is a widely used synthetic red dye with applications in confectionery, pharmaceuticals and cosmetics. Animal studies link excessive intake to thyroid tumors and behavioral effects in children, prompting the WHO to recommend a maximum daily intake of 0.1 mg/kg body weight. Reliable monitoring of trace levels in food products is vital for consumer safety and regulatory compliance.

Objectives and Study Overview

This application note evaluates a rapid, portable surface-enhanced Raman scattering (SERS) method for detecting trace amounts of Erythrosine B in sugar using the Metrohm Instant SERS Analyzer (MISA). The aim is to establish detection limits, confirm identification in spiked and commercial sugar samples, and demonstrate a straightforward protocol adaptable to field testing.

Methodology

The analytical workflow involves a simple solvent extraction followed by SERS measurement:

• Sample Preparation: Sugar samples spiked with EB at 100, 50, 25 and 10 µg/g were dissolved in ethanol (100 mg in 1 mL) and rested for 5 minutes.
• SERS Assay: 100 µL of the ethanolic extract was combined with 800 µL gold nanoparticle colloid and 100 µL 0.5 M NaCl, shaken, and introduced into the MISA vial attachment for analysis.
• Field Protocol: Three to four scoops of any sugar sample are extracted similarly in a 2 mL vial and mixed with Au NP and NaCl for on-site screening.

Used Instrumentation

The following components comprise the SERS platform:

• MISA Advanced (Metrohm Instant SERS Analyzer) featuring Orbital-Raster-Scan technology
• MISA Vial Attachment and P-SERS Attachment for flexible sampling
• ID Kit – Gold Nanoparticles (Au NP) with disposable spatula, pipettes and sample vials
• Software: Misa Cal V1.0.15; Firmware 0.9.33; Laser power 5; Integration time 1 s; 10 averages; Raster ON

Main Results and Discussion

SERS spectra of ethanolic extracts demonstrated reliable detection of EB down to 10 µg/g in spiked sugar. Overlaid, baseline-corrected spectra matched a reference library entry created from a 5 µg/mL standard, confirming signature Raman peaks. Analysis of a commercial pink decorating sugar sample yielded consistent identification despite minor peak shifts, underscoring the robustness of the library matching.

Benefits and Practical Applications

The MISA-based assay offers several advantages over conventional laboratory techniques (e.g., HPLC, CE):

• Portability and on-site applicability with battery operation
• Rapid turnaround (minutes) with minimal sample preparation
• Low consumable requirements and limited user training
• Cost-effectiveness for routine food safety surveillance

Future Trends and Opportunities

Emerging developments may enhance this SERS platform for broader analytical tasks:

• Integration of multiplexed libraries for simultaneous detection of multiple additives and contaminants
• Improved nanoparticle substrates to boost sensitivity and reproducibility
• Automation and AI-driven spectral interpretation for real-time decision support
• Smartphone-based interfaces and cloud connectivity for distributed monitoring networks

Conclusion

The Metrohm Instant SERS Analyzer provides a rapid, sensitive and field-deployable solution for trace detection of Erythrosine B in sugar. Its simplicity, speed and portability position it as a competitive alternative to laboratory methods, supporting effective regulatory compliance and consumer protection.

References

No external literature references were provided in the source document.