Lab Quality & Testing
HPLC vs Mass Spectrometry: Two Questions, Two Instruments
HPLC separation and mass spectrometry provide complementary evidence, with distinct limits. Learn what each method can and cannot establish.
Published August 23, 2026 · 6 min read
By Novanta Research · Substantively reviewed October 1, 2026
Evidence scope: Analytical evidence only. This comparison does not address clinical evidence, sterility, endotoxin status, or suitability for human use.
What HPLC measures
Reverse-phase high performance liquid chromatography separates components of a sample by how strongly they interact with a hydrophobic stationary phase as a solvent gradient runs through the column. Each component leaves the column at a characteristic retention time and produces a peak.
Area-percent purity is commonly calculated from the target peak relative to the total integrated peaks detected under the stated method conditions. It is method-dependent: co-elution, detector response, wavelength, integration rules and reporting thresholds affect what is represented. It is not a direct measurement of peptide mass in the vial and does not independently establish identity.
Sources for this section
- Validation of Analytical Procedures Q2(R2) — International Council for Harmonisation, 2023
- Related impurities in peptide medicines — Journal of Pharmaceutical and Biomedical Analysis, 2014
What mass spectrometry measures
Mass spectrometry ionizes analytes and measures mass-to-charge ratios. Comparing observed data with the expected molecular mass can support identity and can reveal some mass-shifted impurities, depending on the instrument, sample preparation and validated method.
A mass match is not a complete sequence determination and may not distinguish isomeric or isobaric species. Raw signal intensity is also not a purity percentage unless it comes from a suitable quantitative, validated method.
Sources for this section
- Validation of Analytical Procedures Q2(R2) — International Council for Harmonisation, 2023
- Related impurities in peptide medicines — Journal of Pharmaceutical and Biomedical Analysis, 2014
Why one without the other fails
HPLC and mass spectrometry provide complementary evidence, but the strength of a conclusion depends on method suitability, specificity, reference materials and acceptance criteria. Even used together, they do not establish sterility, endotoxin status, net peptide content or suitability for human use.
Novanta's posted lot reports must be read individually for their HPLC purity results and stated identity methods. The currently posted reports do not include peptide mass-spectrometry results. ICP-MS elemental-impurity screening does not establish peptide molecular identity. The Certifications page remains the source for the methods and results reported for each lot.
Sources for this section
- Validation of Analytical Procedures Q2(R2) — International Council for Harmonisation, 2023
Keep reading
For laboratory and research use only. Not for human or veterinary consumption. Novanta Research is not a compounding pharmacy and nothing in this article is medical advice or a claim that any compound diagnoses, treats, cures or prevents any condition.