Kinsey, C., et al. A Versatile Reversed-Phase Liquid Chromatography Charged Aerosol Detection Method for Streamlined Monitoring of QS-21 Content and Stability in Liposomal Adjuvant Formulations. https:// doi.org/10.26434/chemrxiv.15002275/v1. Posted on 21 April 2026 (this preprint has not been peer reviewed. Data may be preliminary)

This study introduces a novel, versatile liquid chromatography method coupled with charged aerosol detection (LC-CAD) for the reliable quantification and stability monitoring of QS-21, widely used in vaccine formulations. Uniquely leveraging fused-core phenyl hexyl stationary phases and in silico optimization, the method effectively separates QS-21 isomers and its hydrolyzed degradant, QS-21 HP, with high sensitivity and specificity suitable for quality control environments.

The importance of this work lies in addressing the analytical challenges associated with QS-21’s complex structure, low UV absorbance, and hydrolytic instability, which are critical factors influencing vaccine efficacy and safety. By providing a robust, transfer-friendly assay that can monitor QS-21 content and degradation during manufacturing and storage, this paper significantly advances the tools available for ensuring the consistent quality of saponin-based adjuvants, supporting their broader application in safe and effective vaccine development.

While the method exhibits strong initial performance, the authors emphasize the importance of continued validation, multi-site testing, and refinement to fully realize its potential for routine quality control and process analytics in vaccine development.