Methodology
How we verify peptides
Every sample is analyzed independently at ETH Zurich using ESI-TOF mass spectrometry. We have no affiliation with any peptide vendor. Our methodology is fully open.
Analytical technique
We use electrospray ionisation time-of-flight mass spectrometry (ESI-TOF MS). The technique ionises the sample under mild conditions and separates ions by their exact mass-to-charge ratio, yielding a mass accuracy of <5 ppm against the theoretical monoisotopic mass.
ESI-TOF is the gold standard for confirming peptide identity because it provides unambiguous molecular weight without requiring prior knowledge of the sequence. It is non-destructive and works on microgram quantities.
What we measure
| Measurement | What it tells you |
|---|---|
| Observed m/z | The raw mass-to-charge signal from the instrument |
| Charge state (z) | The number of protons carried by the ion |
| Observed M+H⁺ (Da) | Calculated neutral mass reconstructed from m/z and z |
| Δm (Da) | Absolute difference between observed and expected mass |
| Δppm | Relative mass error — our threshold is ±10 ppm for confirmation |
| Purity (%) | Estimated from relative peak areas in the TIC chromatogram |
Verdict criteria
Δppm ≤ 10 and purity ≥ 95 %. Compound identity and purity meet specification.
Δppm ≤ 10 but purity between 85–95 %. Mass matches; minor impurities present.
Signal quality insufficient for a reliable mass determination. Often caused by poor solubility or degradation.
Observed mass deviates >10 ppm from expected. The sample is not the claimed peptide.
No usable signal detected. Sample may be empty, insoluble, or severely degraded.
Sample requirements
- Quantity: Minimum 0.5 mg lyophilised powder (we use ~0.1 mg; remainder returned or discarded at your request).
- Format: Sealed vial or resealable bag inside the collection pouch we provide.
- Storage: Keep frozen until you insert the sample. Room temperature for shipping is acceptable for up to 72 h.
- Anonymity: Do not write your name on the vial — only your anonymous token. The lab receives unlabelled samples.
Process overview
- 1Register online
Fill in the submission form. You receive an anonymous token and we send you a collection envelope within 2–3 business days.
- 2Receive your envelope
A tamper-evident collection envelope arrives by post. Your anonymous token is printed on the label — no name, no address on the vial.
- 3Insert & post back
Place your sample vial in the envelope, seal it, and post it back to us.
- 4Handed to the lab
We collect your sample and hand it directly to the ETH Zurich facility. Analysis takes 5–7 business days from receipt.
- 5Result published
We format the analytical result and publish it to your account. You receive an email notification and can view the full certificate in your dashboard — with the option to share publicly.
Pricing
LAUNCH PRICEIncludes ESI-TOF MS analysis, full raw data export, purity estimate, and a tamper-evident digital certificate. Invoice issued by email after your sample is received. Payment by bank transfer (IBAN provided on invoice).
Submit a peptide →