How to Read a COA (Certificate of Analysis)

A Simple Guide for Research Use Only

When you’re purchasing research materials, one of the most important documents you’ll see is a COA — a Certificate of Analysis. COAs can look unfamiliar at first, so this guide explains how to read a COA and what each part means, using the simple format we use at Peptide Basix.

If you’re new to research terminology, you may want to start with our article on What Peptides Are.

If you’re new to Certificates of Analysis, start with our guide: What Is a Certificate of Analysis (COA)?

What a COA Shows

A COA is a document from an independent testing lab that evaluates a specific batch of a material.
It confirms:

• the batch that was tested
• the identity of the sample
• the mass or mg of product
• the purity results
• the date it was analyzed
• who submitted it for testing

At Peptide Basix, we use Janoshik Analytical, a third-party lab that provides clear, easy-to-read summary COAs.

For a full breakdown of what a Certificate of Analysis is, who issues them, and what they do (and don’t) mean, see our guide: What Is a Certificate of Analysis (COA)?

What You’ll See on a Janoshik COA

Here’s what each section on our COAs means:

1. Task Number

A unique ID for the test.
This number lets you verify the report directly on the lab’s website to confirm authenticity.

2. Client, Sample, and Batch Information

You’ll see:
• Client: PEPTIDEBASIX LLC
• Sample: The name of the item tested
• Batch: The batch/lot code of the material
• Manufacturer: Peptide Basix

What “Manufacturer” Means Here

On these reports, “Manufacturer” simply refers to the company who supplied the sample to the testing lab.
It does not mean the physical facility where raw materials were originally synthesized.

We list Peptide Basix in that field because we are the company that sourced, handled, and submitted that batch for testing, which is standard for research-supply companies.

3. Sample Photo

The lab includes a picture of the vial or sample they received.

This helps confirm:

• the sample was physically received
• the batch/label matches the test report
• the correct lot was tested

Curious why peptide pucks don’t always look the same? Our post on Why Peptides Look Different explains common variations.

4. Tests Requested

This section shows the type of testing performed.
Janoshik typically evaluates:

• Identity of the sample
• Purity of the sample

Their reports are designed to provide simple, clear results without overwhelming technical pages.

5. Test Results

This is the heart of the COA.

You’ll see:

• Name of the compound
• Amount detected (mg)
• Purity percentage

Example:
Purity: 99.77%

Purity represents how much of the sample is the intended research compound.
Small differences in purity from batch to batch are normal and expected — they don’t indicate quality issues.

If you’d like a deeper look at how HPLC works in analytical chemistry, you can explore this overview from ScienceDirect on High-Performance Liquid Chromatography.

Understanding how to read a COA helps researchers verify batch identity, purity, and documentation accuracy.

6. Verification Code

Each report comes with a verification link or code.

This lets you confirm:

• the test is real
• the data hasn’t been altered
• the batch matches what was tested

Transparency matters, and this verification feature helps ensure authenticity.

7. Date & Signature

The bottom of the COA shows:

• The date the sample was analyzed
• A signature block from the lab

This confirms when the analysis was performed and that the report was issued by the testing lab.

Why COAs Matter

A COA provides clarity and confidence during research by showing:

• the batch that was tested
• when and how it was evaluated
• the purity of the sample
• verification information

It helps ensure researchers know exactly what material they’re working with.

Example COAs can be viewed directly on individual product pages, such as RT-20.

Final Thoughts on How to Read a COA

A COA doesn’t need to be complicated to be useful.
The COAs we provide are simple, clear, and easy to understand — giving researchers transparency into batch identity, purity, and testing verification.

Understanding how to read a COA helps researchers verify batch identity and purity without needing pages of technical data.
If you ever have any questions about how to read a COA or what a result means, we’re always happy to help.

For storage basics, check out our guide on Why Peptides Are Lyophilized

Frequently Asked Questions

Does a COA guarantee product performance?

No. A COA only shows the results of lab testing for identity and purity. It does not predict performance, usage outcomes, or effectiveness of any research material.

Why do COA purity percentages sometimes differ?

Small changes happen because different labs use different equipment, testing methods, or calculation styles. Slight variations are normal in research documentation.

Is purity the same thing as quality?

Not exactly. Purity is a single numerical value from the test. Quality includes other factors like handling, storage conditions, and how accurately the batch was documented.

Why don’t COAs include appearance or reconstitution details?

COAs stay focused on test results only. They do include a sample photo, but they don’t include appearance explanations, solubility behavior, or practical handling notes. Those vary by researcher and aren’t part of analytical testing.