Quantifying Oligonucleotides (CONSUMABLES GUIDE BOOK)

Significance of Topic

Synthetic oligonucleotide therapeutics have seen a major resurgence in the past decade, offering new modalities to target gene transcription and treat a broad range of diseases, from genetic disorders to complex cardiovascular conditions. Accurate quantification of these molecules in biological matrices is essential to support drug discovery, pharmacokinetics, and safety assessments.

Objectives and Study Overview

This guide outlines a comprehensive workflow for reliable LC-MS quantitation of oligonucleotides, covering sample pretreatment, solid-phase extraction, chromatographic separation, mass spectrometric detection, and automation strategies designed to deliver high recovery, sensitivity, and throughput.

Methodology and Instrumentation

• Sample Pretreatment: Detergent-free protein binding disruption using RapiZyme™ Proteinase K with guanidine HCl (6 M) and TCEP (0.5 M) to liberate oligonucleotides from proteins.
• Solid-Phase Extraction: OligoWorks™ SPE devices packed with WAX sorbent selected for lot-to-lot consistency and high recovery (>85 % for lipid-conjugated ASOs and >90 % for unmodified ssDNA).
• Chromatography: MaxPeak™ Premier High-Performance Surface columns reduce nonspecific adsorption, boosting MS signal by up to 12-fold. ACQUITY™ Premier Oligonucleotide BEH C18 ultrashort columns (20 mm) and VanGuard™ FIT guard cartridges support ultra-fast separations (<1 min) and extend column life.
• Detection: Xevo™ TQ-XS tandem quadrupole mass spectrometer for sensitive quantitation at trace levels.
• Automation: Integration with Andrew+™ Pipetting Robot and OneLab™ software enables standardized, kit-based SPE workflows on microplates to improve reproducibility and throughput.

Key Results and Discussion

Using the optimized workflow, average oligonucleotide recoveries exceeded 80 % across plasma, urine, CSF, cellular, and tissue samples. MaxPeak Premier columns delivered a >12-fold increase in MS signal versus standard hardware, enabling lower limits of quantitation. Rapid on-off elution behavior on ultrashort columns achieved baseline separation of oligonucleotides in under one minute. The VanGuard FIT format demonstrated effective protection of analytical columns and simplified maintenance.

Benefits and Practical Applications

• Robust recovery and consistency across diverse sample types.
• Enhanced sensitivity and lower detection limits for trace-level quantitation.
• Rapid, high-throughput LC methods suitable for large sample batches.
• Extended column lifetime and reduced downtime through guard cartridge design.
• Automated, reproducible workflows compatible with standard liquid-handling platforms.

Future Trends and Possibilities

Advances in surface chemistries and column technologies may further reduce nonspecific adsorption and shorten run times. Integration with digital lab management and AI-driven method optimization will streamline method development. Emerging applications include quantitation of increasingly complex oligonucleotide conjugates, mRNA therapeutics, and direct measurement in single-cell analyses.

Conclusion

The described sample preparation and LC-MS workflow offers a robust, sensitive, and scalable solution for quantitative bioanalysis of therapeutic oligonucleotides. By combining optimized enzymes, SPE sorbents, advanced column chemistries, and automation, laboratories can achieve high throughput and reproducibility critical for drug development.

References

• Araya et al. Elements of robust SPE-based oligonucleotide extraction. Consumables Guide Book.
• Brennan et al. Application Note 720007019EN: Improved Oligonucleotide SPE-LC-MS Analysis Using MaxPeak High Performance Technology.
• Lardeux et al. High-Throughput Chromatographic Separation of Oligonucleotides: A Proof of Concept Using Ultra-Short Columns. Analytical Chemistry 2023, 95 (27), 10448–10456.