How to Read a Certificate of Analysis

A Certificate of Analysis (COA) is one of the most important documents in research supply quality assurance. It provides documented evidence that a product meets its stated specifications.

## Key Sections of a COA

### 1. Product and Batch Information

The top section identifies the product name, batch/lot number, manufacturing date, and expiration date. Always verify that the batch number on the COA matches the batch number on your product vial.

### 2. Appearance

This section describes the physical appearance of the material (e.g., white lyophilized powder, clear solution). Any deviation from expected appearance may indicate a quality issue.

### 3. Identification

Confirms the identity of the compound using analytical methods such as:

- Mass Spectrometry (MS) — confirms molecular weight

- Retention Time matching — confirms identity via HPLC

### 4. Purity Analysis

HPLC (High-Performance Liquid Chromatography) analysis shows the purity percentage. A single dominant peak indicates high purity. Specifications typically require ≥98% or ≥99% purity.

### 5. Content/Assay

This section shows the actual measured content compared to the stated content. For example, a 5mg vial might have an assay result of 5.1mg, which would be within typical specification ranges.

### 6. Residual Solvents

If applicable, this section reports any residual solvents detected during analysis, measured in parts per million (ppm).

### 7. Endotoxin Testing

For sterile products, endotoxin levels are reported and compared against specification limits.

## What to Look For

- Match the batch number on the COA to your product

- Verify the purity meets the stated specification (≥98% or ≥99%)

- Check that the appearance description matches the product

- Confirm the COA is signed and dated by a qualified analyst

## Storing COAs

We recommend maintaining a organized digital archive of all COAs for your records. They serve as important documentation for quality assurance and research reproducibility.