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 Best-Peptides, we guarantee ≥99% purity, meaning the main peak accounts for at least 99% of the total peak area.
Retention Time
The retention time indicates when the compound elutes from the column. This is characteristic for each peptide under specific conditions and helps confirm identity.
Minor Peaks
Small peaks represent impurities, which may include:
- Deletion sequences (missing amino acids)
- Incomplete deprotection products
- Oxidized forms
- Aggregates
Understanding Purity Percentages
| Purity Level | Typical Use | Quality Assessment |
|---|---|---|
| ≥99% | Premium research | Excellent |
| 95-98% | Standard research | Good |
| 90-95% | Preliminary studies | Acceptable |
| <90% | Not recommended | Poor |
The Certificate of Analysis (COA)
A comprehensive COA should include:
Essential Information
- Peptide name and sequence: Confirms identity
- Molecular weight: Theoretical and observed (via MS)
- HPLC purity: Percentage and method details
- Batch number: For traceability
- Date of analysis: Freshness indicator
Supporting Data
- HPLC chromatogram image
- Mass spectrometry data
- Appearance description
- Storage recommendations
Mass Spectrometry Confirmation
While HPLC tells you about purity, mass spectrometry (MS) confirms molecular identity:
- Expected mass: Calculated from sequence
- Observed mass: Measured value
- Acceptable variance: Typically ±1 Da
Red Flags to Watch For
Be cautious of suppliers who:
- Don’t provide COAs
- Show low-resolution chromatograms
- Have significantly different observed vs. expected masses
- Lack batch-specific documentation
Why 99% Purity Matters
Higher purity means:
- More reliable research results
- Better reproducibility
- Fewer confounding variables
- Accurate dose-response relationships
Best-Peptides Quality Standards
Every peptide we sell undergoes:
- HPLC Analysis: Verified ≥99% purity
- Mass Spectrometry: Molecular weight confirmation
- Visual Inspection: Appearance check
- Documentation: Full COA with chromatogram
Conclusion
Understanding HPLC purity and COA reports empowers you to make informed decisions when purchasing research peptides. Always verify that your supplier provides comprehensive analytical documentation—it’s the hallmark of a quality-focused company.
At Best-Peptides, transparency is our commitment. Every product includes full COA documentation, downloadable directly from the product page.