Rapid and sensitive UHPLC screening of food dyes in carbonated beverages using UV/Vis wavelength switching

Importance of the Topic

Rapid and sensitive detection of food dyes in carbonated beverages is essential to ensure regulatory compliance and protect consumer health. Many synthetic dyes are restricted or phased out due to potential adverse effects, thus fast and accurate screening methods are required.

Study Objectives and Overview

• Demonstrate the Hypersil GOLD VANQUISH C18 column and Vanquish Flex Binary UHPLC for rapid separation of ten common dyes.
• Assess method linearity, reproducibility, and recovery in beverage samples.
• Illustrate the use of UV/Vis wavelength switching to enhance sensitivity.

Methodology and Instrumentation

Separation employed a 50 mm × 2.1 mm, 1.9 μm Hypersil GOLD VANQUISH C18 column with a binary UHPLC system equipped with a diode array detector and a 2 μL LightPipe flow cell. Mobile phases consisted of 20 mM ammonium phosphate buffer (pH 8.8) and a 50/50 buffer–acetonitrile mixture under a gradient at 0.55 mL/min and 40 °C column temperature. Samples were degassed, diluted, spiked with standards, and filtered through 0.45 μm nylon filters. Calibration standards covered 1–30 μg/mL using primary and mixed working solutions prepared in water. Data was acquired and processed with Chromeleon 7.2 software.

Main Results and Discussion

• Baseline separation of ten dyes was achieved in approximately two minutes with resolution >1.5.
• Reproducibility was excellent (retention time, peak area, and width RSDs generally <0.5%).
• Calibration curves were linear (R2 between 0.9997 and 1.0000).
• Screening of three commercial beverages detected new coccine and sunset yellow FCF; concentrations ranged from 1.9 to 97.7 μg/mL.
• Spike recoveries were ≥80% (mostly ≥95%), indicating minimal matrix interference.
• Wavelength switching based on 3D diode array data improved signal-to-noise ratios by up to nine-fold.

Benefits and Practical Applications

This UHPLC method enables high-throughput, reliable screening of dyes in beverages, offering rapid run times and robust quantification with low detection limits. It supports quality control and regulatory monitoring in food and beverage industries.

Future Trends and Potential Applications

Further developments may include integration with mass spectrometry for confirmatory analysis, extension to other matrices such as juices and wines, automation of sample preparation and data processing, and real-time in-line monitoring in production environments.

Conclusion

The combination of the Hypersil GOLD VANQUISH C18 column and Vanquish Flex Binary UHPLC system delivers rapid, sensitive, and reproducible analysis of food dyes in carbonated beverages. Wavelength switching significantly enhances sensitivity, making this approach well suited for routine food safety and quality control.

References

• Lamb A. Application Note 21672. Thermo Fisher Scientific; Runcorn, UK; 2017.