Documentation / COA
How to read a peptide
Certificate of Analysis.
Every peptide reference standard ships with a COA. Here's what each section means, what thresholds to expect, and which red flags to watch for.
What a COA is
A Certificate of Analysis is a per-lot document that reports analytical test results for a specific manufactured batch. For peptides, the COA is your primary evidence that what's in the vial matches what's on the label. Without it, you're trusting a brand name.
1 / HPLC purity
High-Performance Liquid Chromatography separates a peptide sample into its component peaks. The main peak is your target molecule; smaller peaks are impurities, truncations, or oxidation products.
What to look for: the main peak area as a percentage of total peak area. ≥99% is the research-grade standard. ≥95% is acceptable for some exploratory work. Below 95% introduces too much analytical noise for reference work.
Red flag: a COA that reports purity without showing the chromatogram. The chromatogram tells you where the impurities sit relative to your target peak — critical if those impurities co-elute during your own assay.
2 / Mass spectrometry identity
Mass spec confirms the molecular weight of the main peak. For a peptide, the observed m/z should match the theoretical mass within ±0.5 Da for low-resolution MS, or ±0.01 Da for high-resolution.
What to look for: theoretical mass, observed mass, and delta. If the COA reports only one of those, something is being hidden.
3 / Endotoxin (LAL assay)
The Limulus Amebocyte Lysate assay detects bacterial endotoxins. For research-use peptides where the standard will be handled in cell culture, endotoxin levels matter because they can confound your downstream data.
What to look for: endotoxin value reported in EU/mg (endotoxin units per milligram). Below 1 EU/mg is typical for research-grade material.
4 / Water content
Karl Fischer titration or loss-on-drying measures residual water in the lyophilized cake. High water content shortens shelf life and can shift the mass of your weighed sample.
What to look for: ≤5% water content for long-term stability.
5 / Lot number and date
Every COA must reference a specific lot number that matches the vial label. The synthesis date tells you how old the material is; the retest date (if listed) is the manufacturer's recommended re-verification point.
Red flag: a "generic" COA with no lot number, or one lot number covering multiple vials that look different. Each manufacturing run is a distinct lot with its own COA.
What Lumera Labs publishes
Every Lumera Labs lot has a COA available by lot number. The COA includes: HPLC chromatogram (not just a number), mass-spec identity (theoretical, observed, delta), LAL endotoxin result, water content, lot number, synthesis date, and the analytical method references used.
Verified reference standards
Every lot HPLC-verified. COA on every order.