Peptide Purity
The percentage of target peptide in a sample, measured by HPLC.
Definition
The percentage of the target peptide relative to total peptide content in a sample, typically measured by HPLC. Research-grade peptides usually have ≥95% purity, while pharmaceutical-grade requires ≥98%.
In More Detail
Peptide purity is calculated as the area of the main HPLC peak divided by the total area of all peaks, expressed as a percentage. The remaining percentage represents impurities such as deletion sequences, truncated peptides, oxidized variants, and synthesis byproducts. Purity values can vary based on the wavelength used (214 nm vs 220 nm vs 280 nm) and the detection method. Independent verification is the only way to confirm a supplier's purity claim, since our internal data shows 73% of peptides we test fall short of the labeled value by an average of 8.4 percentage points.