HPLC Peptide Purity Testing

Every batch of research peptides sold at PEP&GAIN is verified by High-Performance Liquid Chromatography (HPLC) and confirmed by mass spectrometry (MS) before it leaves our facility. This guide explains what those tests measure, why they matter for in-vitro laboratory research, and how to read a Certificate of Analysis (COA).

1. HPLC — how pure is the peptide?

HPLC pushes a dissolved peptide sample through a chromatography column under high pressure. Molecules interact with the column's stationary phase at different rates, so the target peptide and its impurities elute at different times and appear as separate peaks on a UV detector. The area of the main peak divided by the total area of all peaks gives the peptide's percent purity. For most research applications, ≥ 98% HPLC purity is the accepted benchmark.

2. Mass spectrometry — is it the right peptide?

HPLC confirms how clean the sample is; it does not confirm what the sample is. Mass spectrometry ionises the peptide and measures its exact molecular mass to within a fraction of a Dalton. That measured mass is then compared to the theoretical mass calculated from the peptide's amino-acid sequence. A match confirms the correct sequence; a mismatch flags truncation, deletion, or contamination.

3. The Certificate of Analysis (COA)

A batch-specific COA is issued for every research peptide we ship. It documents:

• Peptide sequence, molecular formula and exact mass
• HPLC chromatogram with % purity
• Mass spectrum with observed vs. theoretical mass
• Appearance, net peptide content, water and counter-ion content
• Batch / lot number and manufacture date

4. Storage and handling

Lyophilised research peptides are stable long-term at −20 °C in a desiccated, light-protected environment. Reconstituted peptides should be stored at 2–8 °C and used within the window listed on the COA. Repeated freeze–thaw cycles degrade sequence integrity and should be avoided.

For in-vitro laboratory research only. Not for human consumption.