Determination of pyrrolizidine alkaloids in plant material using SFC-MS/MS

Significance of the Topic

Pyrrolizidine alkaloids (PAs) are plant-derived compounds with potential carcinogenic and hepatotoxic properties. Their presence in food, beverages and herbal products poses a long-term health risk. Sensitive and selective analytical methods are essential for monitoring PAs to ensure consumer safety and regulatory compliance.

Objectives and Study Overview

The study aimed to develop and validate a rapid SFC-MS/MS method for qualitative and quantitative analysis of 34 PAs and their N-oxides in plant matrices. It focused on achieving baseline separation of critical isomeric pairs and demonstrating applicability to commercial tea samples.

Methodology and Instrumentation

Sample preparation involved acidic extraction of tea samples followed by pH adjustment and solid phase extraction on C18 cartridges. After elution and evaporation, samples were reconstituted in methanol and centrifuged prior to analysis.

Used Instrumentation

• Supercritical fluid chromatograph: Nexera UC, Shimadzu
• Chiral column: CHIRALPAK® IG-3 (0.3 × 10 cm, 3 µm)
• MS/MS detector: LCMS-8060, Shimadzu with ESI in positive mode

Main Results and Discussion

Method optimization screened various column-modifier combinations to resolve five Lycopsamin and two Senecionine stereoisomers within an 8-minute gradient. Calibration in black tea matrix exhibited strong linearity (R² > 0.99) over 2–200 µg/kg with S/N > 10 for LLOQs. Analysis of ten commercial teas detected PAs above LLOQ in four samples, demonstrating method robustness in complex matrices.

Benefits and Practical Applications

• Rapid analysis with high throughput due to short run time
• Enhanced selectivity and stereoisomer resolution via chiral SFC
• Sensitive quantification suitable for regulatory monitoring in food and herbal products

Future Trends and Applications

Advancements may include coupling SFC with high-resolution mass spectrometry for non-target screening, expanding to other plant toxins, and integrating automation in sample preparation for large-scale monitoring programs. Further exploration of alternative chiral stationary phases could refine isomeric separations.

Conclusion

The developed SFC-MS/MS method offers a robust, sensitive, and fast approach for analyzing 34 PAs in plant materials. Its successful application to commercial teas highlights its potential for routine safety testing and regulatory compliance.

References

• EFSA Journal 2017;15(7):4908. Risks related to pyrrolizidine alkaloids in honey, tea, herbal infusions and supplements.
• BfR-PA-Tee-2.0/2014. Determination of pyrrolizidine alkaloids in plant materials using SPE-LC-MS/MS.