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. 2021 Nov;59(11):1107-1115.
doi: 10.1002/mrc.5160. Epub 2021 Apr 27.

Structural determination of four manufacturing impurities of D&C Red No. 33

Eugene P Mazzola  1 , Adrian Weisz  2 , Douglas P Ridge  3 , Sarah E Donnelly  4 , Hanwen Zhang  1 , Raquel M Gonzalez  5 , Luke K Ackerman  4 , Kristen L Reese  4 , Clark D Ridge  4
Affiliations

Structural determination of four manufacturing impurities of D&C Red No. 33

Eugene P Mazzola et al. Magn Reson Chem. 2021 Nov.

Abstract

Four manufacturing impurities of D&C Red No. 33 isolated by counter-current chromatography were analyzed by NMR and ESI mass spectrometry. Three of these impurities were reported previously with minimal details of structural determination. All four are structurally related to the main component of the dye. The fourth exhibited an unusual discrepancy between the NMR structure and its chemical formula suggested by ESI-MS results. Structural determination and assignment of the main component and four impurities are discussed as well as resolution of the discrepancy between the NMR and ESI-MS results of the fourth impurity.

Keywords: D&C Red 33; NMR assignment; azo dyes; food dyes; structure elucidation.

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References

REFERENCES

    1. Code of Federal Regulations, 21 CFR 74.1333, 74.2333, D&C Red No. 33, U.S. Government Printing Office, Washington, DC, 2020.
    1. A. P. Rosholt, CTFA International Color handbook, 4th ed, The Cosmetic, Toiletry, and Fragrance Association, Washington, DC 2007.
    1. S. J. Bell, E. P. Mazzola, B. Coxon, Dyes Pigments 1989, 11, 93.
    1. E. P. Mazzola, S. A. Turujman, S. J. Bell, J. N. Barrows, J. E. Bailey Jr., E. G. Mouchahoir, S. Prescott, M. D. Archer, M. Oliver, W. F. Reynolds, K. W. Nielsen, Tetrahedron 1996, 52, 5691.
    1. E. P. Mazzola, S. J. Bell, S. A. Turujman, J. N. Barrows, J. E. Bailey Jr., J. B. McMahon, T. K. Germann, W. F. Reynolds, Can. J. Chem. 1999, 77, 1941.