Peptide Purity & Testing Standards

Peptide Purity and Testing: HPLC, MS and COA Basics

Peptide quality cannot be reduced to a single percentage. Identity, chromatographic purity, content, related impurities, water content and physical stability are different attributes, and each analytical method answers a different question.

Scientific illustration comparing chromatographic purity and mass-spectrometry identity testing.
Purity and identity are complementary analytical questions: chromatography separates detected components, while mass spectrometry supports molecular-identity assessment.

Identity, purity and content are not synonyms

  • Identity asks whether the material matches the expected compound or sequence.
  • Chromatographic purity describes the relative distribution of detected peaks under a stated method.
  • Content concerns how much target material is present in a defined quantity.
  • Impurity profile considers related species, degradation products and other detected components.

A high main-peak percentage does not, by itself, prove molecular identity or establish exact vial content.

What HPLC contributes

High-performance liquid chromatography separates components according to their interaction with a stationary phase and mobile phase. Reversed-phase HPLC is widely used for peptide characterisation. Results depend on the method, detector, integration rules, reference materials and sample preparation, so a number should be read with its analytical context.

What mass spectrometry contributes

Mass spectrometry provides molecular-mass information and can support identity assessment. LC-MS combines chromatographic separation with mass detection. More detailed sequence or impurity work may use tandem or high-resolution techniques. Orthogonal methods are valuable because no single test captures every quality attribute.

How to read a Certificate of Analysis

A useful COA should identify the product, batch or lot, test method, result, specification where applicable, test date and responsible laboratory or reviewer. Check whether the document refers to the exact batch on the listing and whether the stated method supports the claim being made.

NutriMax analysis information

Visit Lab Analysis for available NutriMax documentation. Researchers should review the original report and their own method requirements rather than relying solely on a marketing summary.

Selected references