HPLC Purity Testing & Certificate of Analysis Guide
HPLC (high-performance liquid chromatography) is the analytical method used to verify peptide purity. This guide explains how HPLC works, how to read a Certificate of Analysis (COA), and why independent batch testing matters for researchers in India.
What is HPLC?
High-performance liquid chromatography separates compounds based on their chemical properties as they pass through a chromatographic column. For peptides, reverse-phase HPLC is the standard method — it separates the target peptide from impurities, truncated sequences, and residual solvents.
The output is a chromatogram: a graph showing peaks over time. The area under the main peak, expressed as a percentage of total peak area, is the purity value. A 99% purity result means 99% of the detected material is the target peptide.
How to Read a Certificate of Analysis
A COA should include: (1) the peptide name and sequence, (2) the HPLC purity percentage, (3) the batch number, (4) the molecular weight, (5) the appearance description, and (6) the testing date.
At RetraLabs, every order includes a COA. Researchers can request the full HPLC chromatogram to independently verify the purity claim. If a supplier cannot provide HPLC data, that is a red flag.
Why Independent Batch Testing Matters
The Indian research peptide market includes sellers who re-label bulk powders without testing. Without independent HPLC verification, there is no way to confirm the vial contains what the label claims.
RetraLabs tests every batch independently — not relying on manufacturer certificates alone. Batches below 98% purity are rejected. This is the verification gap RetraLabs was built to fill.
Frequently Asked Questions
What is a good peptide purity percentage?
Research-grade peptides should be at least 98% pure by HPLC. RetraLabs peptides are tested to 99%+ purity.
What is a COA?
A Certificate of Analysis (COA) documents the HPLC purity result, batch number, molecular weight, and identity confirmation for a peptide batch. It is the primary quality document for research peptides.
Can I get the HPLC chromatogram for my order?
Yes. RetraLabs provides the full HPLC chromatogram on request for any batch. The COA is included with every order.
Research Use Only — All products mentioned in this guide are supplied strictly for in-vitro laboratory research and analytical purposes. Not intended for human consumption.
