Multiple Heart-cut 2D-LC/MS with UNIFI Informatics for Compliant Monitoring of Monoclonal Antibody Charge Variants

Significance of the Topic

The characterization of monoclonal antibody charge variants is critical to ensure biopharmaceutical quality and efficacy. Traditional ion exchange methods rely on salt gradients that hinder direct mass spectrometry coupling, leading to offline fractionation and desalting. A compliant two-dimensional LC/MS approach bridges incompatible separations, reduces handling steps, and provides robust, real-time mass confirmation of protein variants.

Study Objectives and Overview

This study demonstrates a multiple heart-cut 2D-LC/MS workflow to analyze infliximab lysine variants. The first dimension employs ion exchange chromatography with a salt gradient to resolve charge variants. Selected fractions are transferred to a second dimension for reversed-phase liquid chromatography coupled to mass spectrometry, enabling intact mass measurement without offline desalting.

Methodology and Instrumentation

The workflow uses a Waters ACQUITY UPLC system with 2D technology and UNIFI software. Key steps include:

• First dimension separation on a BioResolve SCX mAb column with MES buffer and salt gradient (pH 6.60, 10–55 mM over five minutes)
• Multiple heart-cut selection of each lysine variant based on retention time repeatability
• Trap column wash and transfer to an ACQUITY UPLC Protein BEH C4 column for the second dimension
• Intact mass analysis on the MS with data processed via UNIFI intact protein workflow and component table generation

Main Results and Discussion

Each lysine variant was successfully isolated and analyzed in a single injection. Deconvoluted spectra showed clear mass peaks for each variant. The measured mass error for the three most abundant glycoforms per variant was approximately 10 ppm, matching expected instrument performance. The workflow demonstrated high retention time reproducibility, essential for precise heart cuts.

Benefits and Practical Applications

The multiple heart-cut 2D-LC/MS method offers:

• Direct coupling of non-MS compatible ion exchange separations to MS
• Elimination of offline fractionation and desalting steps
• Improved throughput and reduced sample handling
• Compliant data acquisition and reporting via UNIFI software

This approach supports rigorous charge variant monitoring in biopharmaceutical development and quality control environments.

Future Trends and Opportunities

The described 2D-LC/MS strategy can be extended to other molecules requiring complex separations, such as glycoproteins or antibody-drug conjugates. Advances in buffer systems, trap chemistries, and informatics automation will further enhance resolution, sensitivity, and regulatory compliance. Integration with real-time process analytics holds promise for continuous manufacturing applications.

Conclusion

Implementing a multiple heart-cut 2D-LC/MS workflow with UNIFI informatics provides a robust solution for direct analysis of monoclonal antibody charge variants. The method streamlines sample handling, ensures accurate mass confirmation, and supports compliance, making it valuable for modern biopharmaceutical laboratories.

Reference

1. Auto·Blend Plus technology Home Page. Waters Corporation. Accessed January 2020.