LC-MS Oligonucleotide Impurity Analysis: Trace Peak Centric vs Progressive Deconvolution Data Processing

Reliable oligonucleotide impurity profiling demands the right data processing strategy.

Protein Metrics put two head-to-head using Byos Oligo on triplicate Agilent DNA 40mer LC-HRMS data — matching masses to clips, shortmers, longmers, substitutions, and modifications within 10 ppm, with fully automated reporting throughout.

• TPC: Built for Reproducibility: UV trace peaks drive the workflow, with Byos AutoCompute integrating 10 peaks per sample automatically. UV-only estimates 90% FLP purity; the UV-MS hybrid — adjusting UV area using MS intensity ratios to resolve co-eluting impurities — corrects this to 70%, both with RSD < 10%. Simpler, faster, and versatile across UV, MS, and UV-MS quantitation modes. The high-throughput QC workhorse.
• PD: Built for Sensitivity: Overlapping time-window deconvolution with signal processing finds what TPC misses. PD detected 31 additional impurity mass assignments, and its single mass-per-impurity output eliminates the duplicate assignments that trail multiple trace peaks. The tradeoff: higher %RSD on XIC AUC quantitation due to limited MS scans per peak — faster acquisition or broader LC peaks would fix this.
• Both Detect > 100 Impurities: TPC and PD both identified the FLP and over 100 impurity masses below 0.01% relative MS abundance — including the full clip series from 6-mer to 39-mer. They're not competing methods; they're complementary ones. Use PD to hunt low-abundance impurities during development. Use TPC when reproducibility and regulatory-ready quantitation are non-negotiable.