HPLC purity in peptides
The purity of every EXOMA research peptide is verified by reverse-phase high-performance liquid chromatography (HPLC). The exact percentage of each batch is documented in its Certificate of Analysis (COA), and that is the value published — not a generic catalog figure. Reagents for scientific research use only (RUO).
HPLC methodology
How the purity of a peptide is measured, step by step. A reverse-phase protocol based on USP guidelines and adapted to synthetic peptides.
- Sample preparation — Dissolution in mobile phase with 0.22 μm filtration to remove particles that would interfere with the chromatographic reading.
- Chromatographic separation — C18 reverse-phase column (250 × 4.6 mm, 5 μm). Acetonitrile/water gradient with 0.1% TFA. Flow rate 1.0 mL/min.
- Detección UV a 220 nm — Wavelength optimized for the peptide bond. 20 μL injection with a diode array detector (DAD).
- Purity calculation — Area normalization: % purity = (main peak area / total area) × 100. All impurities > 0.1% are reported.
What does HPLC measure?
HPLC separates the components of a sample according to their affinity for the stationary and mobile phases. The main peak area relative to the total peak area determines the peptide's purity percentage: the higher that percentage, the lower the proportion of impurities or synthesis fragments.
Our standard
- C18 — Reverse-phase column.
- 220 nm — Detección UV.
- % per batch — The measured purity is reported in the COA.
- 1 batch = 1 COA — Trazabilidad.
Release standard and per-batch traceability
Each batch is released with its Certificate of Analysis, which states the HPLC-measured purity of THAT batch — not a generic catalog value. If a batch does not meet the purity specification stated in its own COA, a replacement or full refund is offered.
Cross-verification with mass spectrometry
HPLC quantifies purity; mass spectrometry (MS) confirms that the measured molecular mass matches that of the expected peptide. Together, both techniques validate identity and purity, not just one of the two.
The per-batch COA is the source of truth
The purity value specific to each batch is in its Certificate of Analysis, downloadable and verifiable by batch number. Every order includes the COA corresponding to the vials shipped.
FAQ
What is HPLC purity and why does it matter?
HPLC (high-performance liquid chromatography) is the analytical standard for quantifying the purity of a peptide. A purity of ≥99% indicates that at least 99% of the content corresponds to the target molecule, with less than 1% impurities, synthesis byproducts or degradation. For research, higher purity means more reproducible results and fewer confounding variables.
What is the difference between ≥95% and ≥99% purity?
A peptide at 95% contains up to 5% impurities: truncated fragments, residual amino acids and salts. At 99%, those impurities are reduced to less than 1%, which translates into greater experimental precision and more reliable results in in vitro and in vivo models.
How do I verify the purity of a peptide I buy?
The supplier should include a Certificate of Analysis (COA) with the HPLC chromatogram, showing the main peak and any impurities detected. Verify that the COA is specific to the batch (batch number) you received and not a generic document for the compound.
What standards does EXOMA use to validate its purity?
Each batch is analyzed by reverse-phase HPLC following protocols derived from the USP (United States Pharmacopeia). Additionally, mass spectrometry (LC-MS) is performed to confirm molecular identity, along with an endotoxin assay by the LAL method.
Does purity degrade over time?
Yes. Lyophilized peptides maintain their purity for 24 to 36 months at -20 °C. Once reconstituted, degradation accelerates: store at 2-8 °C and use the vial within 21 to 30 days. Exposure to UV light, heat and freeze-thaw cycles are the main factors in loss of integrity.