An Integrated Workflow for Intact and Subunits of Monoclonal Antibody Accurate Mass Measurements

Importance of the Topic

Monoclonal antibodies are a major class of biologics requiring precise molecular characterization for regulatory approval and quality control. Accurate measurement of intact mass and subunits is complicated by large size, heterogeneous glycosylation patterns, and complex disulfide bonding.

Objectives and Study Overview

This study presents an end-to-end automated workflow to measure accurate mass of intact monoclonal antibodies and their subunits. The approach integrates automated sample preparation on the Agilent AssayMAP Bravo platform with UHPLC/Q-TOF analysis and specialized data processing, aiming to improve throughput, reproducibility, and reduce hands-on time.

Methodology and Instrumentation

Affinity capture of antibodies from CHO cell culture supernatant was achieved using streptavidin microcartridges loaded with biotinylated HER2 extracellular domain or Protein L. On-cartridge reactions included PNGase F deglycosylation, IdeS proteolysis, and TCEP reduction to generate glycoforms and subunits without manual transfers. Eluates were collected and neutralized prior to UHPLC separation.

Used Instrumentation

• Agilent AssayMAP Bravo platform
• Agilent 1290 Infinity II UHPLC with PLRP-S column
• Agilent 6545XT AdvanceBio Q-TOF with Dual Agilent Jet Stream source
• Agilent MassHunter BioConfirm software

Key Results and Discussion

Automated purification yielded highly pure intact antibodies with retention of structural integrity. Intact mass measurements achieved sub-10 ppm accuracy for both a therapeutic mAb (Herceptin) and NIST reference material. Subunit analysis confirmed efficient deglycosylation and proteolysis with clear resolution of light and heavy chains and F(ab')2 fragments. Throughput was improved, completing multiple sample sets within hours versus a full day manually.

Benefits and Practical Applications

This automated workflow reduces manual variability, enhances reproducibility, and frees analysts from labor-intensive sample preparation. It supports routine biotherapeutic QC, batch-to-batch comparison, and rapid post-translational modification analysis in development and manufacturing settings.

Future Trends and Opportunities

Advances in microfluidic automation, higher throughput mass spectrometry platforms, and integrated bioinformatics will further streamline antibody characterization. Extending this approach to diverse biotherapeutic modalities and multiplexed PTM mapping can accelerate biologics development.

Conclusion

The integration of automated sample preparation with high-resolution LC/Q-TOF and advanced data analysis provides a robust solution for accurate mass measurement of intact antibodies and subunits, enhancing efficiency and data quality in monoclonal antibody characterization.

References

1. Chames P, Baty D. Bispecific antibodies for cancer therapy. mAbs. 2009;1(6):539-547.
2. Wang DL, et al. Precise Characterization of Intact Monoclonal Antibodies by the Agilent 6545XT AdvanceBio LC/Q-TOF. Agilent Technologies. 2018.
3. Beck A, Wagner-Rousset E. Characterization of Therapeutic Antibodies and Related Products. Anal Chem. 2013;85(2):715-736.
4. Zhang Q, Bateman KP. Automated DBS microsampling, microscale automation and microflow LC-MS for therapeutic protein PK. Bioanalysis. 2016;8(7):649-659.