What does COA mean for peptide research?

COA stands for Certificate of Analysis. It documents batch-specific testing such as purity, identity, mass, and sometimes sterility or endotoxin results.

Does higher purity always mean a product is appropriate?

Not by itself. Purity is important, but identity testing, storage, handling, and intended research context also matter.

What is the COA Explainer?

It is a free educational tool from Volta Peptides designed to help researchers plan, compare, or interpret peptide-related information more consistently.

All Tools

COA Explainer

Understand every section of a Certificate of Analysis. Learn what each test measures, what good results look like, and what red flags to watch for.

COA Fields Explained

What it measures

High-Performance Liquid Chromatography (HPLC) separates the peptide from impurities and measures the percentage of the desired peptide in the sample. It is the single most important quality indicator on a COA.

What a good result looks like

Purity of 98% or higher is considered research-grade quality. Pharmaceutical-grade peptides typically exceed 99%. Anything above 95% is generally acceptable for research purposes.

Red flags

Purity below 95%
No HPLC chromatogram image included
Vague language like "high purity" without a specific percentage
Purity reported without specifying the method (e.g., HPLC vs UV)

Good result

Purity (HPLC)

99.2%

Concerning result

Purity (HPLC)

87.4%

Verifying COA Authenticity

Check the batch/lot number

Every legitimate COA should have a unique batch or lot number that matches the label on your vial. Contact the vendor if they do not match.

Look for a third-party lab

The most trustworthy COAs come from independent, accredited third-party laboratories rather than in-house testing. Look for the lab name, address, and accreditation number.

Verify the lab exists

Search for the testing laboratory online. Legitimate labs have websites, physical addresses, and verifiable accreditations (ISO 17025, GMP, etc.).

Request the raw chromatogram

A genuine COA should include or be able to provide the actual HPLC chromatogram (the graph showing peaks), not just a purity number. Reluctance to provide this is a red flag.

Cross-reference with the vendor

Some vendors allow you to enter a batch number on their website to pull up the corresponding COA. This helps verify the document was not fabricated.

Check the date and formatting

Professional COAs have consistent formatting, proper letterhead, test dates, analyst signatures or identifiers, and look like professional laboratory documents rather than simple text documents.

Quick Reference: Minimum Acceptable COA

HPLC Purity: > 95%
Mass Spec: within +/- 1 Da
Endotoxin: < 5 EU/mg
Sterility: No growth (14-day)
Peptide content: > 65%
Batch number matches vial

Why COAs matter

A Certificate of Analysis is the primary document verifying the identity, purity, and quality of a peptide product. Without a valid COA from a reputable laboratory, there is no way to confirm what is actually in a vial. Always request and review the COA before purchasing from any vendor.

COA Explainer for peptide research

Understand every field on a Certificate of Analysis. Use this page as a practical research worksheet, then compare the result against product labels, COAs, and related Volta guides before making any research decision.

Interpret certificate of analysis values

Check peptide mass, purity, or sequence properties

Evaluate lab-readiness before research use

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