Investigating UPLC Ion Mobility Mass Spectrometry: A New Approach to Authentication and Routine Screening of Ginsenoside Isomers in Functional Food Products

Significance of the Topic

The authentication and routine screening of ginsenoside isomers in functional food products is essential for ensuring product quality, safety and efficacy. Ginsenosides are steroidal saponins whose bioactivity varies by isomeric form and source species. Conventional chromatographic and mass-based methods struggle to distinguish closely related isomers in complex extracts, which can lead to mislabeling or incorrect potency claims.

Objectives and Study Overview

This study explores a novel non-targeted workflow combining ultra-performance liquid chromatography (UPLC) with ion mobility-mass spectrometry (IM-MS) and collision cross section (CCS) screening to authenticate and profile ginsenoside isomers in Korean ginseng, red panax and gingko biloba products. The goal was to demonstrate enhanced selectivity, reproducibility and reduced reliance on high-purity standards.

Methodology and Instrumentation Used

The analytical setup included:

• ACQUITY UPLC I-Class system with HSS T3 column (100 mm × 2.1 mm, 1.8 µm).
• SYNAPT G2-Si ion mobility-QTOF MS operating in negative ESI mode.
• UNIFI Scientific Information System and MassLynx software for data processing.

Key parameters:

• Gradient elution over 20 min using 0.1% formic acid in water (A) and acetonitrile (B).
• IM wave velocity ramp (1000→300 m/s) in nitrogen drift gas.
• Acquisition range m/z 50–1200, collision energy ramp 35–75 eV.

Main Results and Discussion

Combining UPLC with ion mobility separation increased peak capacity and resolved coeluting matrix components. CCS measurements provided a robust second identification point for isomeric pairs:

• Rb2 vs. Rc: measured TW CCS_N2 361.77 vs. 350.58 Ų (error <0.5%).
• Rd vs. Re: 328.89 vs. 333.11 Ų.
• Rf vs. Rg1: 304.70 vs. 295.83 Ų.

An unknown isomer at 7.88 min drift time was readily characterized (TW CCS_N2 358.80 Ų) and added to the CCS library. Consecutive week analyses showed CCS reproducibility within 0.5% for all markers.

Benefits and Practical Applications

This assay enhances confidence in compound identification, reveals hidden isomers, and streamlines data interrogation via spectral cleanup. Reduced dependence on expensive reference standards (cost >£2400) translates to significant cost savings. The approach is readily applicable to quality control in nutraceutical, herbal and functional food industries.

Future Trends and Applications

Building comprehensive CCS libraries will broaden the method to diverse botanicals. Regulatory frameworks may adopt CCS screening as a confirmatory tool. Integration with high-throughput workflows could accelerate authenticity testing and brand protection. Ongoing improvements in drift-tube design and software analytics will further refine sensitivity and throughput.

Conclusion

The UPLC-IM-MS CCS screening workflow provides a powerful, non-targeted approach to authenticate and quantify ginsenoside isomers in complex matrices. By combining chromatographic, mass and mobility dimensions, the method achieves unrivaled selectivity, reproducibility and cost efficiency for routine screening.

References

1. Ligor T., Ludwiczuk A., Wolski T., Buszewski B. Isolation and determination of ginsenosides in American ginseng leaves and root extracts by LC-MS. Anal Bioanal Chem. 383(7-8):1098–1105 (2005).
2. Waters Technical Note No. 720005374en. The use of Collision Cross Section (CCS) Measurements in Food and Environmental Analysis (2015).