System Performance Check (SPC): A Readiness Companion to Multi-Attribute Method (MAM) Analysis in Biopharmaceutical Quality Control

Background/Objectives: The multi-attribute method (MAM) is a powerful LC-MS workflow for site-specific monitoring of critical quality attributes (CQAs) in biopharmaceutical products, but its sensitivity to LC drift, ionization variability, and mass-calibration shifts has slowed adoption in routine quality control. A blank injection confirms that the system is clean; it does not confirm that the system is ready. This work evaluates a system performance check (SPC) workflow, built around a 13-peptide LC/MS reference standard designed against the system-readiness metrics in USP General Chapter 1060, as a readiness assessment performed before MAM sample analysis. Methods: The workflow was run on a recently installed Agilent 6230C LC/TOF with OpenLab CDS and the integrated MAM for OpenLab CDS, following routine instrument tune and calibration. The 13-peptide mix probes mass accuracy, retention time, peak area and height, in-source fragmentation, methionine oxidation, chromatographic resolution, and sodium and iron adduct formation; it also includes a heavy-to-light peptide pair for a single-point, low-abundance response check and a deamidated peptide pair to monitor a clinically important post-translational modification. Triplicate injections were evaluated against per-target acceptance criteria: mass accuracy (±10 ppm or ±13 ppm for EYK), retention-time %RSD (≤0.5%), and, for a subset of targets, peak-area %RSD (≤10%). Results: Across the three replicates, all thirteen peptides met every acceptance criterion applied to them. The twelve primary targets met their mass-accuracy and retention-time criteria, and the relative-area monitors (sodium and iron adducts, methionine oxidation, the heavy/light detector check, and the deamidation pair) met theirs. The asparagine deamidation pair was detected and reproducibly measured as a relative-area ratio at the +2 and +3 charge states in every replicate (6.7 to 7.0% at +2 and 7.5 to 7.8% at +3, against a <8% criterion), demonstrating reproducible relative monitoring of a clinically important post-translational modification. Conclusions: The SPC workflow provides a single, evidence-backed readiness measurement prior to MAM sample analysis, and it produces documentation, including the audit trail and electronic-signature functionality in OpenLab CDS 3.0, aligned with data-integrity expectations.