Understanding a HPLC analysis certificate : guide for non-chemist researchers
HPLC purity, molecular weight, endotoxins, heavy metals—a peptide COA contains a wealth of information about the product's true quality. This guide teaches you how to read it in 9 minutes.
What is a COA and why is it essential?
Un COA (Certificate of Analysis / Certificat d’Analyse) is a document issued by an independent analytical laboratory that attests to the measured characteristics of a specific batch of peptide. It is objective proof of the product's quality.
Without a COA, you have no way of verifying:
- That the peptide is indeed the one announced (molecular identity)
- That the purity corresponds to what the seller claims
- That the product does not contain dangerous contaminants (endotoxins, heavy metals)
- The analyzed batch matches the one you received.
At MyPeptide, each batch is analyzed by Janoshik Analytical, an independent European laboratory specializing in HPLC chromatography for research peptides. The COA is available and downloadable before purchase.
Basic COA information: header
The first section of the COA contains the identification metadata:
| Field | What it means | What you check |
|---|---|---|
| Peptide name / CAS | Identity of the molecule analyzed | Corresponds to the product ordered |
| Batch number | Unique identifier of the manufactured batch | Corresponds to the number engraved/printed on your vial |
| Date of analysis | When the analysis was carried out | Recent (< 6 months prior to delivery) |
| Issuing Laboratory | Who performed the analysis? | Recognized independent laboratory (e.g., Janoshik) |
| Quantity analyzed | Sample mass | Representative (mg, not µg) |
If the Certificate of Analysis (COA) is issued by the seller's own laboratory and not by an independent third party, its value is very limited. A seller who analyzes their own production has a clear conflict of interest. Always demand a COA from an independent third-party laboratory.
HPLC purity — the key figure
La HPLC purity is the percentage of the chromatogram area attributed to the main peak (your peptide) relative to all detected signals. This is the most important parameter of the COA.
How is HPLC purity measured?
- 99%+ : Excellent. Pharmaceutical standard. The peptide is very pure with minimal residual impurities.
- 98-99% : Very good. Acceptable for the majority of research protocols.
- 95-98% : Okay. Acceptable, but significant impurities may interfere with certain sensitive protocols.
- < 95%: Insufficient for serious scientific research. Impurities can bias the results.
HPLC purity measures relative purity compared to compounds detectable by the UV/DAD detector usedImpurities lacking chromophores (and therefore lacking UV absorption) will not be detected by HPLC-UV. This is why HPLC-MS analysis (with mass spectrometry) is even more reliable, as it detects all ionizable species.
Molecular identity by mass spectrometry (MS)
Mass spectrometry (MS) confirms that the analyzed compound does indeed have the expected molecular mass for the target peptide. It appears in the COA in different forms:
- Theoretical molecular mass: calculated from the sequence
- Measured molecular mass: from the mass spectrometer
- The two values must correspond to within < 5 Da (or < 5 ppm for high-resolution devices)
A mass mismatch may indicate: an incorrect sequence, a post-synthesis modification (oxidation, accidental glycosylation) or a substituting peptide.
Bacterial endotoxins
THE Endotoxins Lipopolysaccharides (LPS) are fragments of bacterial cell wall released during bacterial lysis. They are highly pyretic (fever-inducing) and pro-inflammatory, even in minute quantities.
The endotoxin test by the LAL (Limulus Amebocyte Lysate) method is expressed in EU/mg (Endotoxin Units per milligram):
| Endotoxin levels | Acceptability | Use |
|---|---|---|
| < 0.1 EU/mg | Excellent | Sensitive research, studies on cell cultures |
| < 1 EU/mg | Very good | Majority of research protocols |
| < 5 EU/mg | Acceptable | Less sensitive protocols |
| > 5 EU/mg | Problematic | Risk of experimental bias (induced inflammation) |
The MyPeptide threshold is < 0.1 EU/mg for all batches. High endotoxin levels are one of the most common causes of false positives in inflammation and immunology studies.
Heavy metals
Heavy metal analysis detects the presence of potentially toxic inorganic contaminants introduced during SPPS synthesis (catalysts, solvents, equipment):
- Lead (Pb): USP threshold < 0.5 ppm
- Cadmium (Cd): USP threshold < 0.2 ppm
- Arsenic (As): USP threshold < 0.15 ppm
- Mercury (Hg): USP threshold < 0.015 ppm
A reliable Certificate of Analysis (COA) indicates "Not Detected" (ND) or the measured values for each of these elements. Peptides synthesized in Europe generally have very low heavy metal profiles thanks to the quality of the solvents and equipment used.
The HPLC chromatogram — visual reading
The chromatogram is the time/absorbance graph that often accompanies the Certificate of Analysis (COA). It allows for a visual assessment of purity:
- A single large peak: ideal — the peptide is very pure
- A large peak + small satellites: acceptable if the satellites represent < 2% of the total area
- Several comparable peaks: Problematic — significant impurities present
- High baseline (noise): may indicate a complex matrix or unresolved impurities
Why Janoshik Analytical?
MyPeptide has partnered with Janoshik Analytical for independent analysis of each batch. Janoshik is a European laboratory recognized in the research peptide community for:
- Specialization in HPLC-MS chromatography for peptides
- Total independence (no capital link with manufacturers)
- Transparent publication of raw (unadjusted) results
- Public database searchable by batch number
- Accreditation according to European analytical standards
Each Janoshik COA has a unique report number. You can verify its authenticity directly on the Janoshik Analytical website by entering the report number. If a supplier's COA cannot be verified this way, it may be counterfeit.
All MyPeptide COAs are available before purchase.
Each MyPeptide product sheet includes the "COA / Purity" tab with direct PDF download of the Janoshik certificate — without registration, without email.