Streamlined LC-MS/MS Method for Screening Unauthorized Synthetic Dyes in Children's Foods

It is imperative that effective analytical methods are in place for the assessment of risks posed by synthetic dyes in food products, especially those that are marketed to children, who represent a vulnerable population. These dyes include a variety of chromophore classes and exhibit variable acidic and basic properties which make their extraction from complex food matrices difficult, as well as increase the likelihood of undetected contaminants. Researchers at the University of Central Florida (Orlando) applied a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the screening of unauthorized acidic and basic dyes in hard candies and breakfast cereals-categories associated with high consumption among children. A paper based on their efforts was published in Food Chemistry.¹

In 2025, the FDA reasserted their previous efforts to regulate synthetic food dyes by focusing on creating clearer rules and ensuring the safety of foods made for babies and young children.² While many analytical methods has been used to investigate the presence of approved food dyes in candy and cereal samples,^3-6 only a limited number of studies in comparison have done the same for unauthorized dyes,^7-13 an observation by the research team which inspired their study.

Target analytes for this study included Basic Red 1, Basic Red 2, Basic Red 9, Solvent Red 23, Acid Violet 17, Acid Yellow 3, Acid Red 151, and Red 40. “These eight dyes,” write the authors of the study,¹ “represent a deliberately diverse set chosen for their complementary chemical structures, charge types, solubility behaviors, and spectral properties. Together, they cover the major dye classes (cationic, anionic, and non-ionic) and span a wide range of chromophores (azo, triphenylmethane, and solvent dyes). Their range of ionic states and solvent affinities makes the group suitable for studying dye interactions across multiple environments, including biological, textile, environmental, and polymer systems. Additionally, these dyes are commercially available, well-characterized, and chemically stable, which supports reproducibility and standardization in laboratory or industrial applications. Overall, the set provides a compact, yet comprehensive representation of the behaviors seen across the broader landscape of synthetic colorants.”¹

“This study,” the authors continued,¹ “leverages the high selectivity of tandem mass spectrometry to facilitate the extraction and chromatographic separation of both acidic and basic dye classes. The methodology employed is notably streamlined, minimizing matrix interference and enabling robust quantification. Analytical performance metrics— including sensitivity, specificity, detection limits and recoveries — were excellent across all targeted analytes. Given that all dyes investigated are explicitly banned by the FDA, achieving detection thresholds in the sub-parts-per-billion range is critical for effective surveillance. Although none of the prohibited dyes were detected in the analyzed food samples, discrepancies in product labeling underscore the necessity for routine analytical screening, particularly in high-risk categories such as confectionery and breakfast cereals.”

The research team believes that their findings “highlight a broader issue of labeling transparency and accuracy, suggesting that current packaging practices may not reliably reflect the true composition of food products. Continued monitoring and method refinement are essential to ensure consumer safety and regulatory compliance.”¹

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References

1. Nauth, S. D.; Hitt, B.; Campiglia, A. D. LC-MS/MS Method for Detecting Eight Unauthorized Synthetic Dyes in Confectionery and Breakfast Cereals. Food Chem. 2026, 512, 148876. DOI: 10.1016/j.foodchem.2026.148876
2. HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in the Nation's Food Supply. FDA website 2025. https://www.fda.gov/news-events/press-announcements/hhs-fda-phase-out-petroleum-based-synthetic-dyes-nations-food-supply
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