Method transfer case study for instrument and LC column migration of the purification and analysis workflow for synthetic oligonucleotides

Importance of the Topic

Oligonucleotides serve as essential research, diagnostic and therapeutic agents. Their synthesis yields complex mixtures containing truncated sequences and degradation products. High-resolution purification and rigorous quality control are critical for applications such as qPCR, forensic analysis and gene therapy. Efficient method transfer between different liquid chromatography platforms enhances laboratory flexibility, reduces development time and maintains stringent purity standards.

Study Objectives and Overview

This case study demonstrates a complete transfer of semi-preparative reversed-phase HPLC purification and QC workflows for dual-labeled 15mer oligonucleotides. The original method on an Agilent 1260 Infinity II Preparative-Scale system was migrated to the Thermo Scientific Vanquish Analytical Purification LC platform. Purification performance, yield, purity and identity verification by UHPLC-HRMS were compared across different columns and instruments.

Methodology and Instrumentation

Reagents included crude dual-labeled oligonucleotides, TEAA buffer, acetonitrile and methanol. Samples were dissolved and sonicated before injection.

• Purification: Vanquish Analytical Purification LC System with Daisogel SP-100 ODS-P and Hypersil GOLD C18 semi-prep columns. Chromeleon CDS controlled fraction collection based on UV detection at 260, 350 and 560 nm.
• LC-UV QC: Vanquish Flex Binary UHPLC System. Analytical columns compared: Waters ACQUITY UPLC BEH C18 versus Hypersil GOLD C18. Gradient reversed-phase separation at 50°C, detection at 260 nm.
• LC-HRMS QC: Vanquish Flex UHPLC coupled to Orbitrap Exploris 480. Proprietary aqueous and organic solvents, heated to 30°C. Data analysis and deconvolution via Xcalibur and FreeStyle Xtract.
• Concentration and quantification: Samples dried using SpeedVac concentrator and quantified by UV-Vis at 260 nm on a SpectraMax spectrophotometer.

Key Results and Discussion

Semi-prep purification of ABY-MGB and JUN-MGB showed improved resolution on Hypersil GOLD prep columns compared to Daisogel, reducing shoulder peaks and lowering fraction volumes by 10–20%. QC analysis on Hypersil GOLD analytical columns yielded purities of 99.7–99.9%, matching or exceeding results on Waters columns. LC-HRMS confirmed the expected monoisotopic masses within ±0.2 Da and absence of major impurities. Yields measured by UV-Vis were comparable between the source and Vanquish systems, demonstrating successful method transfer.

Benefits and Practical Applications

• Seamless migration of purification and QC methods between vendors reduces method redevelopment effort.
• Hypersil GOLD columns deliver high resolution and shorter collection windows, decreasing solvent evaporation time.
• Integrated Vanquish workflows under Chromeleon CDS enable automated fraction collection and data management.
• Validated QC by both UV and HRMS ensures compliance with purity requirements for downstream use.

Future Trends and Applications

Advances in column chemistry and UHPLC hardware will continue to improve separation of modified oligonucleotides. Integration with automated sample prep and inline mass spectrometry can further accelerate high-throughput workflows. Emerging ligation and conjugation chemistries will demand tailored purification strategies. Cloud-based data analytics and machine learning may predict optimal gradient and column conditions, streamlining method development.

Conclusion

The transfer of oligonucleotide purification and QC from a non-Thermo Fisher LC platform to the Vanquish system was achieved without compromising yield or purity. Hypersil GOLD prep and analytical columns performed on par or better than the original columns. Combined UHPLC-UV and HRMS workflows under Chromeleon CDS offer a robust solution for high-purity oligonucleotide production.

Reference

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