KATHORSPeptides
← Kathors

Documentation

Understanding a certificate of analysis.

A research buyer's confidence comes from the paperwork as much as the material. This page explains what a certificate of analysis is, the parameters typically reported for a research-grade peptide, and how to read one.

01 — The certificate of analysis

One document that describes exactly what a lot is.

A certificate of analysis (COA) is the record of the analytical tests run on a specific lot of material. It ties a batch to its results: what was measured, by which method, and what the method found.

Because results are lot-specific, a certificate of analysis reflects a particular batch — not a generic template — which is what makes it useful for recordkeeping and reproducibility on the buyer's side. Analytical documentation for a given lot is available on request.

02 — The analyses

Standard characterization parameters.

These are the parameters commonly reported for a research-grade peptide. Each describes a measurable property of the material itself.

ParameterTypically reported
ParameterMethodWhat it tells you
IdentityMS (ESI / MALDI)Confirms the observed molecular weight matches the theoretical weight for the stated sequence.
PurityRP-HPLCReports purity as an area percentage from reversed-phase chromatography.
Net peptide contentAAA / %NDistinguishes the peptide mass from associated water and counterion, so quantities are accurate.
Water contentKarl FischerMeasures residual moisture in the lyophilized material.
CounterionIC / HPLCReports the salt form (for example, acetate or trifluoroacetate) carried with the peptide.
AppearanceVisualDescribes the physical form, typically a white to off-white lyophilized powder.

03 — Reading your COA

How to check a lot against its paperwork.

  • 01

    Match the lot number

    Confirm the lot number on the COA matches the label on the container you received. The document describes that batch specifically.

  • 02

    Check identity first

    Compare the observed molecular weight from mass spectrometry against the theoretical value. They should agree within the method's tolerance.

  • 03

    Read purity in context

    Note the HPLC purity figure and the method conditions. Purity is only meaningful alongside the method that produced it.

  • 04

    Account for net content

    Use net peptide content, water, and counterion figures when precise material amounts matter for your records.

  • 05

    File it with the material

    Keep the COA with your lot records so results stay traceable to the batch throughout its use in your facility.

04 — Storage & handling

General handling for lyophilized material.

These are standard laboratory practices for handling lyophilized peptide powder. Specific conditions should follow your own facility's protocols.

Store cold

Keep lyophilized material frozen and desiccated, protected from light and moisture, for stability during storage.

Warm before opening

Allow a sealed container to reach room temperature before opening to reduce condensation on cold material.

Limit cycles

Minimize repeated freeze–thaw cycles, which can affect material over time. Aliquot where appropriate.

05 — Lot numbers

Lot numbers and traceability.

A lot number identifies a specific batch of material and lets it be matched to its documentation. That link is what lets a result be traced back to a particular batch if a question comes up later.

Questions about a lot or its documentation? Contact us and reference the lot number on your container.

Research only — not for human consumption