High-Resolution and High-Speed Simultaneous Analysis of Preservatives in Cosmetics Using SPP Column

Importance of Topic

Cosmetic formulations often contain water and oils that can support microbial growth, leading to changes in product quality and safety. Regulatory bodies in Japan and Europe require preservatives to ensure product stability over a specified shelf life while limiting concentrations to prevent adverse skin reactions. High‐throughput, reliable analytical methods are essential for routine quality control and regulatory compliance in the cosmetics industry.

Objectives and Overview of the Study

This study demonstrates a rapid, high‐resolution UHPLC method for simultaneous quantification of 24 cosmetic preservatives regulated by the Japanese Ministry of Health, Labour and Welfare and the European Commission. The goal was to achieve complete separation and accurate determination of these compounds in under ten minutes, enabling efficient screening of both standard solutions and commercial lotion samples.

Methodology and Instrumentation

A Shimadzu Nexera UHPLC system equipped with a Shim-pack Velox C18 superficially porous particle (SPP) column was employed. Key chromatographic conditions included a binary mobile phase (aqueous phosphate buffer pH 3.8 and methanol/acetonitrile 9:1), a gradient program spanning 0–9 minutes, a 1.0 mL/min flow rate, 45°C column temperature, and a 1 μL injection volume. Detection was performed by a photo diode array detector monitoring at 254 nm and 280 nm.

Used Instrumentation

• UHPLC system: Shimadzu Nexera series
• Column: Shim-pack Velox C18 SPP (100 mm × 3.0 mm I.D., 2.7 μm)
• Detector: SPD-M40 photo diode array, semi‐micro cell

Main Results and Discussion

• All 24 target preservatives were baseline‐resolved within approximately 9 minutes in standard mixtures at 50 mg/L.
• Chromatograms of commercial lotions A, B, and C revealed consistent detection of phenoxyethanol, methylparaben, and ethylparaben in all samples, with propylparaben additionally found in lotion C.
• Quantified preservative levels ranged from 11.2 to 261.6 mg/100 g, all below the 1000 mg/100 g regulatory threshold.

Benefits and Practical Applications

This UHPLC‐SPP approach offers significant advantages for cosmetic QC laboratories: faster throughput, high chromatographic efficiency, reduced solvent consumption, and reliable quantification of a broad panel of preservatives. It supports compliance with stringent safety standards and facilitates routine monitoring of product stability.

Future Trends and Potential Applications

• Integration with automated sample preparation to further increase laboratory productivity.
• Expansion of the method to include emerging preservatives and degradants.
• Application in cross‐matrix analyses, such as emulsions, creams, and serums, to address complex formulation challenges.
• Coupling with mass spectrometric detection for enhanced sensitivity and structural confirmation.

Conclusion

The described UHPLC method using a Shim-pack Velox SPP column provides a rapid, high‐resolution solution for the simultaneous determination of 24 cosmetic preservatives. It ensures regulatory compliance, enhances analytical throughput, and can be adapted for broader applications in cosmetic quality control.

Reference

Shimadzu Application Note L540, April 2019