IDENTIFICATION OF PROHIBITED SKIN LIGHTENING AGENTS IN COSMETIC PRODUCTS USING UHPLC WITH PDA AND MASS DETECTION

Significance of the Topic

The illicit inclusion of pharmaceutical actives such as corticosteroids, hydroquinone and tretinoin in cosmetic products can lead to serious health risks including skin atrophy, permanent discoloration and systemic side effects.
Robust analytical protocols are essential to detect these prohibited agents, ensure regulatory compliance and protect consumer safety.

Objectives and Study Overview

This study aimed to develop and validate a fast, sensitive UHPLC method with photodiode array and mass detection for the simultaneous identification and quantitation of prohibited skin‐lightening agents and common preservatives in cosmetic creams and gels.

Methodology and Used Instrumentation

An acetonitrile extraction was applied to spiked and commercial samples.
Separations were performed on an ACQUITY Arc system equipped with a CORTECS T3 3.0×100 mm, 2.7 µm column using a gradient from 0 to 99 % methanol (0.1 % formic acid) at 0.8 mL/min and 30 °C.
Detection combined a 2998 PDA detector (210–400 nm) and an ACQUITY QDa single‐quadrupole mass detector (ESI+ and ESI–, m/z 100–600).
Empower 3 software provided automated retention‐time matching, UV and mass spectral confirmation, and matrix-matched calibration with R2 > 0.999.

Main Results and Discussion

The method resolved 12 target analytes—including nicotinamide, arbutin, hydroquinone, salicylic acid, four parabens, clobetasol propionate, betamethasone isomers and tretinoin—in under 9 minutes.
Analysis of market samples revealed undeclared corticosteroids (clobetasol propionate, betamethasone 17- and 21-valerate), hydroquinone (>3 % w/w) and tretinoin, often alongside parabens.
UV spectra, accurate m/z and characteristic isotopic patterns provided high‐confidence identification.
Quantitation showed that many products exceeded typical usage or legal limits, posing elevated consumer risk.

Benefits and Practical Application of the Method

• High-efficiency separation of both polar and non-polar analytes in a single run.
• Dual detection (PDA and MS) enhances selectivity and confirmation capability.
• Matrix-matched calibration ensures accurate quantitation in complex cosmetic matrices.
• Suitable for routine quality control, regulatory monitoring and forensic screening of illegal cosmetics.

Future Trends and Possibilities of Use

• Expansion to detect emerging illicit additives and broader chemical classes.
• Coupling with high-resolution MS for non‐targeted screening and suspect screening workflows.
• Development of portable or field‐deployable UHPLC‐based platforms.
• Integration of AI‐driven spectral libraries for rapid automated identification and risk assessment.

Conclusion

The described UHPLC‐PDA‐MS approach with the CORTECS T3 column and Empower 3 software offers a rapid, robust and reliable solution for detecting and quantifying prohibited skin‐lightening agents and preservatives in cosmetics, exposing widespread undeclared actives and supporting enhanced consumer protection.

References

• Desmedt B., Courselle P., De Beer J. O., Rogiers V., Deconinck E., De Paepe K. Illegal cosmetics on the EU market: a threat for human health? Arch. Toxicol. 88:1765-1766 (2014).
• Desmedt B., Van Hoeck E., Rogiers V., Courselle P., De Beer J. O., De Paepe K., Deconinck E. Characterisation of suspected illegal skin whitening cosmetics. J. Pharm. Biomed. Anal. 90:85-91 (2014).
• Fiori J., Andrisano V. LC-MS method for the simultaneous determination of glucocorticoids in pharmaceutical formulations and counterfeit cosmetics. J. Pharm. Biomed. Anal. 91:185-192 (2014).