Mass Spectrometry (LC-MS/MS).

Mass spectrometry (MS), typically coupled with liquid chromatography (LC–MS/MS), is one of the most versatile and powerful analytical platforms. By measuring the mass-to-charge ratio (m/z) of ions, MS enables precise identification, structural characterization, and quantification of biomolecules ranging from small peptides to complex viral capsids. When preceded by liquid chromatography, analytes are first separated to reduce complexity before being introduced into the mass spectrometer, significantly improving resolution and sensitivity.

In the CMC context, LC–MS/MS supports a wide spectrum of assays supporting identity, purity, impurity monitoring, and product characterization. It is not a single method but rather a family of applications that regulatory authorities routinely expect in Biologics License Applications (BLAs) and Marketing Authorization Applications (MAAs).

Specialized Procedures
While this page provides a high-level overview, the following procedure-specific posts explain how MS is applied to critical quality attributes:

Peptide Mapping by LC–MS: For identity confirmation and primary structure verification.

Host Cell Protein Characterization by MS: For detection of process-related impurities.

Intact Mass Analysis (by MS): For confirming whole protein/capsid integrity and glycoform profiling.

5′ Cap Structure Analysis by MS: A key mRNA quality attribute.

Capsid Proteins Characterization by MS: For AAV and LVV structural proteins.

Charge Detection Mass Spectrometry (CDMS): For analyzing genome heterogeneity and aggregation.

Regulatory & Standards Context
Chromatography–MS methods are widely cited across pharmacopeias and regulatory guidance. While general expectations are provided (e.g., USP <125> “Mass Spectrometry”), specific applications like peptide mapping are directly referenced in ICH Q6B and are frequently scrutinized in regulatory submissions. As such, LC–MS/MS serves as a platform that links multiple specialized procedures to defined Quality Attributes.