Simultaneous Analysis of Synthetic Colorants, Including Red No. 3, Using an Organic Silica Hybrid Core-Shell Column

Significance of the Topic

The simultaneous analysis of synthetic food colorants is essential for regulatory compliance and consumer safety. With varying approvals worldwide and recent bans (e.g., Red No. 3 in the U.S.), a reliable, high-throughput method to separate and quantify multiple dyes supports quality control in the food industry.

Objectives and Study Overview

This study aimed to develop and optimize an HPLC method for the concurrent detection of twelve synthetic tar dyes. The approach combined a Shim-pack NovaCore C18-HB core-shell column with LabSolutions MD method-scouting software. The optimized procedure was validated by analyzing Konpeito sugar candy as a real-world sample.

Methodology and Instrumentation

• Sample Preparation: Konpeito dissolved in ultrapure water and filtered through a 0.22 μm membrane.
• Chromatographic System: Nexera X3 Method Scouting System equipped with Shim-pack NovaCore C18-HB (100 mm×3.0 mm I.D., 2.6 μm).
• Mobile Phases: 20 mmol/L ammonium acetate (aqueous) with a gradient of acetonitrile/methanol.
• Software: LabSolutions MD for automated gradient scheduling, solvent blending, and column selection to reduce manual errors.
• Detection: UV absorbance at 254 nm using SPD-M40 detector.

Main Results and Discussion

• Optimal separation achieved with 20 % methanol in acetonitrile, ensuring baseline resolution of critical pairs such as Phloxine B and Acid Red 106 within a 7 min run.
• Comparison with a fully porous column (Shim-pack Scepter C18-120, 150 mm×4.6 mm, 5 μm) showed a >50 % reduction in run time on the core-shell column, thanks to restricted diffusion in the thin porous layer.
• Automated method scouting enabled rapid evaluation of eleven organic solvent ratios, identifying the best conditions without labor-intensive manual adjustments.
• Analysis of Konpeito sugar candy detected Tartrazine (Y4), Sunset Yellow FCF (Y5), and Brilliant Blue FCF (B1) at 50 mg/L, demonstrating method applicability.

Benefits and Practical Applications

The developed method delivers:

• Wide pH tolerance (1–12) due to the organic silica hybrid core-shell stationary phase, enabling flexibility in mobile phase and sample solvents.
• Reduced analysis time and solvent consumption, increasing lab throughput and lowering operational costs.
• Streamlined method development with LabSolutions MD, minimizing human error and speeding up method optimization.
• Suitability for routine QA/QC of synthetic food dyes in various matrices.

Future Trends and Opportunities

• Integration of machine-learning algorithms into method-scouting platforms to predict optimal chromatographic conditions for new analytes.
• Expansion of hybrid core-shell materials across diverse stationary phases for faster, higher-resolution separations.
• Adoption of green chromatographic practices, including alternative solvents and lower organic consumption.
• Development of combined UV-MS workflows for broader target compound coverage and structural confirmation.

Conclusion

The combination of Shim-pack NovaCore C18-HB core-shell column and LabSolutions MD software provides a robust, rapid, and high-resolution HPLC method for twelve synthetic tar colorants. This approach enhances laboratory efficiency, supports regulatory compliance, and offers a practical solution for routine food colorant analysis.

Reference

No external references were provided in the original text.