High Throughput Peptide Mapping with the Vanquish UHPLC System and the Q Exactive HF Mass Spectrometer

Importance of the topic

The structural characterization of biopharmaceutical proteins, especially monoclonal antibodies (mAbs), is critical for ensuring product quality, safety, and efficacy.
High-throughput peptide mapping combines rapid chromatographic separation with high-resolution mass spectrometry to deliver detailed information on primary sequence, post-translational modifications (PTMs) and glycosylation profiles in minimal analysis time.

Goals and overview of the study

This work evaluates a fast analytical platform integrating the Thermo Scientific Vanquish UHPLC system with the Q Exactive HF Orbitrap mass spectrometer.
The objectives were to:

• Assess sequence coverage for light and heavy chains of two model mAbs (Rituximab, Denosumab) over gradients of 30 to 5 minutes
• Monitor key modifications including oxidation, deamidation and glycosylation
• Demonstrate robustness, reproducibility and data quality at ultra-short gradients

Methodology and instrumentation

Sample preparation:

• Denaturation of mAbs in 7 M urea, reduction with DTT, alkylation with IAA and tryptic digestion overnight
• Peptide cleanup and acid quench to pH 3

Chromatography:

• Vanquish UHPLC with 2.1 × 250 mm Acclaim 120 C18 column
• Five gradients from 2–45% ACN (5, 8, 13, 20, 30 min) with flow rates of 1.1 to 0.4 mL/min

Mass spectrometry:

• Q Exactive HF with HESI-II source, data-dependent Top 5 MS/MS
• Acquisition managed by Xcalibur 3.0 and SII software
• Data processing via PepFinder 2.0 for identification/quantification and FreeStyle 1.0 for spectral review

Main results and discussion

Chromatographic performance:

• Efficient peptide separation even at 5 min gradient, with peak widths below 1 s
• High separation efficiency maintained across all gradient lengths

Sequence coverage and PTM profiling:

• 100% sequence coverage achieved for both light and heavy chains at all gradient times
• Quantitative consistency of oxidation, deamidation and glycoforms with standard deviation ≈0.2%
• Robust glycopeptide fragmentation patterns enabled confident identification down to low-abundance species

Data density:

• Typically 6 Full MS and 25 MS/MS scans acquired per chromatographic peak in 5 min runs
• High scan speed of Q Exactive HF ensured sufficient data points for accurate quantification

Benefits and practical applications

• Significant reduction in instrument time per sample supports high-throughput workflows
• Reliable detection and quantification of critical quality attributes (CQAs) such as PTMs and glycosylation heterogeneity
• Robust performance suitable for routine QA/QC in biopharma production and development

Future trends and opportunities

Further acceleration of peptide mapping may be driven by:

• Ultra-high-pressure UHPLC and shorter columns for sub-minute gradients
• Advanced AI-based data processing for automated PTM annotation
• Multiplexed sample introduction and parallel MS acquisition to increase throughput
• Integration with real-time monitoring in continuous bioprocessing

Conclusion

The combined Vanquish UHPLC and Q Exactive HF platform delivers a fast, sensitive and reproducible approach for detailed peptide mapping of mAbs.
Ultra-short gradients down to 5 minutes achieve full sequence coverage and robust PTM quantitation, enabling higher sample throughput and streamlined biopharmaceutical characterization.

Reference

[1] Z. Zhang, Large-scale identification and quantification of covalent modifications in therapeutic proteins. Anal. Chem. (2009) 81, 8354–8364.
[2] X. G. Shah, L. Chen, Z. Zhang, LC-MS/MS peptide mapping with automated data processing for routine profiling of N-glycans in immunoglobulins. J. Am. Soc. Mass Spectrom. (2014) 25, 999–1011.