Testing standard
The Open Peptide Standard (Protocol v1.1) defines the blind sampling rules, three-tier analytical and microbiological test panel, and batch grading scale used for every vial we test.
Every test result and grade under the Open Peptide Standard attaches strictly to the tested batch number and test date—never to a vendor or brand. The Open Peptide Project does not certify, endorse, or penalize vendors.
Three-tier test panel (per batch)
We sample at least two blind vials per batch (one for analytical chemistry, one sealed for microbiological testing, plus a third retained vial where feasible):
- Core tier (every tested batch):
- Identity by LC-MS / HRMS: measured molecular mass within ±0.5 Da (or ±10 ppm by HRMS) of theoretical mass, plus RP-HPLC retention-time match where a reference standard exists. Failed identity is an automatic overall Fail.
- Purity by RP-HPLC: peak area percentage with method, detection wavelength (214–220 nm), and full chromatogram published, plus individual impurity reporting.
- Vial content (quantity): HPLC assay against a reference standard (within ±10% of labeled amount [90.0%–110.0%] is passing, with lab measurement uncertainty reported).
- Injectable tier (vials sold for reconstitution / injection):
- Bacterial endotoxins (USP <85>): kinetic LAL test reported in EU/vial against a published per-vial cutoff (no per-dose limit is used, as the project does not give dosing advice). Exceeding the cutoff is an automatic overall Fail.
- Sterility / bioburden (USP <71>): labeled distinctly as either Pass (USP <71>) or Pass (TAMC/TYMC bioburden only), with the statistical caveat that single-vial testing cannot guarantee lot-wide sterility.
- Full characterization tier (extended & risk-based spot checks):
- Net peptide content: amino acid analysis (AAA) or CHN nitrogen mass balance.
- Water & counter-ion content: Karl Fischer water titration and TFA / acetate counter-ion analysis (USP <503> / <503.1>), reported alongside purity.
- Elemental impurities & residual solvents (risk-based spot checks): ICP-MS heavy metals (USP <232> / <233>) and headspace GC residual solvents (USP <467>).
Tiered HPLC purity grades
Every batch test badge displays the batch number, exact HPLC purity percentage, and test date directly inside the badge. A grade describes only the tested sample from that batch on that date.
| Grade | HPLC Purity | Vial Content (vs. label) | Batch Meaning |
|---|---|---|---|
| A+ · ≥98.0% | ≥ 98.0% | 90.0% – 110.0% (±10%) | Exceeds standard; eligible for Pharma-comparable flag when no single unidentified impurity exceeds 0.5% (and identity & endotoxin pass) |
| Pass · 96.0–97.9% | 96.0% – 97.9% | 90.0% – 110.0% (±10%) | Meets standard (identity & endotoxin pass); any single unidentified impurity >1.0% is flagged on the batch report |
| Caution · 92.0–95.9% | 92.0% – 95.9% | 80.0% – 89.9% or 110.1% – 120.0% | Below passing purity or content tolerance; published with a Caution badge on the batch report |
| Fail · <92.0% | < 92.0% | < 80.0% or > 120.0% (or failed identity, endotoxin, or sterility) | Fails standard; automatic overall Fail if LC-MS identity, endotoxin, or sterility fails regardless of HPLC purity |
About the “Pharma-comparable” impurity flag: Added when a batch achieves ≥98.0% RP-HPLC purity and the lab reports no single unidentified impurity above 0.5%, referencing the FDA 2021 synthetic peptide ANDA guidance benchmark (≤0.5% any new impurity; ≥0.10% identified). That FDA guidance applies formally to five specific generic drugs, not gray-market peptides; the flag means comparable on that analytical measure only, never “pharmaceutical grade” or “safe.” If individual impurities are not reported, the flag reads “Not assessed.”
Blind testing process
- Testing by an ISO/IEC 17025-accredited lab with method scope covering peptide HPLC and LC-MS
- Samples bought anonymously at full retail price (never vendor-supplied; vendor certificates are not accepted)
- Blind sample codes so the lab does not know the source
- Every result published automatically within 7 days of the lab report arriving, pass or fail
- Batch-only scope: grades attach strictly to the tested batch number and test date, expire after a stated period, and never certify, endorse, or penalize a vendor