When sourcing research peptides, purity is the single most important specification to verify. A peptide with 85% purity contains 15% unknown compounds — impurities that can confound experimental results, produce off-target effects, or render data irreproducible.
What HPLC Measures
High-Performance Liquid Chromatography (HPLC) separates a peptide sample by passing it through a column under high pressure. Each compound travels at a different rate based on its chemical properties, producing a chromatogram — a graph of peaks over time.
The area under each peak corresponds to the quantity of that compound. Purity is calculated as the target peptide's peak area divided by the total area of all peaks, expressed as a percentage.
A 99%+ HPLC purity rating means that 99% or more of the measurable compound in the sample is the intended peptide sequence.
Why 95% Is Not Enough
In pharmacological research, even small concentrations of contaminants can produce measurable biological effects. If a study uses a peptide at 95% purity, results attributed to the target compound may actually be caused by the 5% impurity fraction — particularly if those impurities are biologically active degradation products or truncated sequences.
For reproducibility and publication-quality research, 99%+ purity is the accepted minimum standard.
What to Look For in a COA
Every batch we ship includes a Certificate of Analysis from an independent third-party laboratory. A credible COA should include:
- HPLC chromatogram with retention time and peak areas
- Calculated purity percentage
- Molecular weight confirmation via mass spectrometry
- Batch or lot number for traceability
- Laboratory name and date of analysis
If a supplier cannot provide a third-party COA with these elements, the peptide should not be used in research contexts.
All products are strictly for laboratory and in-vitro research purposes only.