Applying a Novel Glycan Tagging Reagent, RapiFluor-MS, and an Integrated UPLC-FLR/QTof MS System for Low Abundant N-Glycan Analysis

Importance of the Topic

N-glycan profiling is essential for characterizing biotherapeutics and ensuring product quality. Conventional fluorescent tags like 2-AB often limit mass spectrometric sensitivity, making detection of low-abundance glycoforms challenging.

Objectives and Study Overview

This study assesses RapiFluor-MS, a rapid fluorescent and MS-active labeling reagent, in combination with an integrated UPLC-FLR/QTof MS system to enhance detection and structural analysis of minor N-glycans from human and mouse IgG samples.

Methodology and Instrumentation

Released N-glycans were labeled with RapiFluor-MS in under five minutes and purified via solid-phase extraction. Chromatographic separation was performed on an ACQUITY UPLC H-Class system with a Glycan BEH Amide column (2.1×150 mm, 1.7 µm) at 60 °C using a gradient of 50 mM ammonium formate (pH 4.4) and acetonitrile. Detection combined FLR monitoring and high-resolution MS on a Xevo G2-XS QTof operating in positive ESI sensitivity mode with DDA-CID (15–40 eV) and UNIFI for data processing.

• GlycoWorks RapiFluor-MS N-Glycan Kit
• ACQUITY UPLC H-Class System
• ACQUITY UPLC Glycan BEH Amide Column
• ACQUITY UPLC FLR Detector
• Xevo G2-XS QTof Mass Spectrometer
• UNIFI Scientific Information System

Key Results and Discussion

RapiFluor-MS yielded over 100-fold improvement in MS sensitivity compared to 2-AB, enabling confident detection of glycoforms at ~0.1% abundance. Uniform FLR responses were observed across glycan species. MS/MS fragmentation provided clear glycosidic cleavages from both reducing and non-reducing ends and characteristic oxonium ions. Minor glycoforms A2G2S1 in human IgG and immunogenic FA2Gal1Sg1 in mouse IgG1 were successfully characterized.

Benefits and Practical Applications

This workflow offers rapid sample preparation, enhanced detection of low-abundance glycan species, and robust structural elucidation, supporting comprehensive glycoform profiling in biopharmaceutical quality control.

Future Trends and Applications

Advances may include coupling with ion mobility separation, high-throughput automation, AI-driven spectral interpretation, and expanded glycan databases for clinical and research applications.

Conclusion

The combination of RapiFluor-MS labeling, UPLC-FLR/QTof MS, and UNIFI software provides a powerful platform for sensitive and detailed analysis of minor N-glycan species in biotherapeutic development and quality assessment.

References

• Rapid Preparation of Released N-Glycans for HILIC Analysis Using a Novel Fluorescence and MS-Active Labeling Reagent. Waters and New England Biolabs application note (p/n 720005275en).
• GlycoWorks RapiFluor-MS Kit Care and Use Manual. Waters Corporation (p/n 715004793en).