What is HPLC and Why Does It Matter?

High-Performance Liquid Chromatography (HPLC) is the gold standard for determining peptide purity. When you purchase research peptides, the Certificate of Analysis (COA) typically includes an HPLC chromatogram that tells you exactly how pure your sample is.

Understanding how to read these reports is essential for any researcher working with peptides.

Reading a Chromatogram

An HPLC chromatogram displays peaks that represent different compounds in your sample. Here’s what to look for:

The Main Peak

The largest peak represents your target peptide. The area under this peak, expressed as a percentage of the total area of all peaks, gives you the purity value. At Peptide Shop, we guarantee ≥99% purity, meaning the main peak accounts for at least 99% of the total peak area.

Retention Time

Each compound has a characteristic retention time—how long it takes to pass through the HPLC column. This helps identify the peptide and confirms you have the correct compound.

Impurity Peaks

Smaller peaks represent impurities, which may include:

  • Deletion sequences - Peptides missing one or more amino acids
  • Truncated sequences - Shortened versions of the target peptide
  • Oxidation products - Oxidised forms of certain amino acids
  • TFA or acetate salts - Counter-ions from the synthesis process

What Purity Level Do You Need?

Different research applications require different purity levels:

  • ≥95% purity - Suitable for initial screening and some in vitro work
  • ≥98% purity - Recommended for most research applications
  • ≥99% purity - Required for quantitative studies and publication-quality research

At Peptide Shop, all our products meet the ≥99% purity standard to support rigorous research requirements.

Verifying Your COA

When you receive your peptides, check the COA for:

  1. Purity percentage - Should match or exceed the stated purity
  2. Retention time - Should be consistent with the known value for that peptide
  3. Clean baseline - Minimal noise indicates quality analysis
  4. Single main peak - The target peptide should dominate the chromatogram

Conclusion

Understanding HPLC reports empowers you to make informed decisions about your research materials. Always request and review the COA for any peptides you purchase, and don’t hesitate to ask your supplier questions about their analytical methods.

For more information about our quality standards, visit our Quality Assurance page.