Data-independent Acquisition (DIA) Approach on Q-TOF Mass Spectrometry for In-depth Peptide Mapping of Monoclonal Antibodies

Significance of the Topic

Peptide mapping ensures accurate characterization of monoclonal antibodies and underpins quality control in biopharmaceutical production. In-depth sequencing of antibody peptides allows verification of primary structure and detection of potential modifications

• Essential for safety and efficacy assessment
• Supports regulatory compliance
• Enables de novo sequence confirmation

Objectives and Study Overview

This study aimed to develop a data independent acquisition approach for de novo peptide sequencing of a bevacizumab biosimilar using a Q-TOF mass spectrometer. Key goals

• Demonstrate full sequence coverage of heavy and light chains
• Validate MS DIA workflow for peptide mapping
• Assess depth and reproducibility of analysis

Methodology and Instrumentation

Sample preparation involved denaturation, reduction with DTT, alkylation with IAA, and overnight trypsin digestion. LC-MS analysis was performed on a Shimadzu LCMS-9030 Q-TOF with Shim-pack GISS-HP column under a gradient of formic acid and TFA in water and acetonitrile. DIA acquisition used 40 Da fixed windows from 210 to 1690 m/z. Data were converted to mzML via LabSolutions and processed in MS-DIAL. Predicted y and b ion transitions were generated in Skyline for fragment verification

• Column: Shim-pack GISS-HP, 150 mm x 3.0 mm, 3 µm
• Flow rate: 0.5 mL/min, oven at 40 °C
• Interface: heated ESI at 300 °C with optimized gas flows

Main Results and Discussion

The DIA approach enabled identification and verification of 61 tryptic peptides covering 100 % of both heavy and light chains. MS/MS spectra matched predicted transitions with high mass accuracy, demonstrating robust de novo sequencing capability. The workflow proved unbiased by capturing all fragment ions in each cycle

• Complete sequence coverage achieved
• High confidence in amino acid assignments
• Reproducible retention times and fragment intensities

Benefits and Practical Applications

This integrated DIA method simplifies peptide mapping by reducing analysis time and dependence on comparative mapping. It supports quality assurance, biosimilar development, and structural verification of mAb products

• Faster workflow than traditional DDA or side-by-side mapping
• Improved reproducibility for QA/QC
• Applicability to diverse protein therapeutics

Future Trends and Applications

Emerging directions include integration of artificial intelligence for automated spectral interpretation, expansion to post-translational modification mapping, higher throughput screening of antibody panels, and adaptation to alternative mass analyzers

• AI-driven de novo sequencing algorithms
• Enhanced PTM characterization
• Automation of end-to-end data processing

Conclusion

The presented DIA strategy on Shimadzu LCMS-9030 Q-TOF demonstrates a powerful, unbiased approach for comprehensive peptide mapping of monoclonal antibodies. It combines robust sample preparation, high-resolution MS/MS acquisition, and advanced data analysis to achieve full sequence coverage and reliable de novo sequencing output.

References

1 Searle BC Pino LK Chromatogram libraries improve peptide detection and quantification by data independent acquisition mass spectrometry Nat Commun 9 5128 2018
2 Prime MS-DIAL software documentation prime psc riken jp Metabolomics Software MS-DIAL index html
3 Skyline software documentation skyline ms wiki home software Skyline page
4 Shimadzu Asia Pacific Application News Peptide Mapping of Monoclonal Antibody Using LCMS-9030 Q-TOF with Shim-pack GISS-HP Column Application News AD-0212B 2019