Peptide purity testing
Purity is the number everyone quotes and the one most often misread. A purity figure is the target peak's share of the total peak area a detector integrated, under one method, at one wavelength. It is a statement about what the method could see, not an absolute statement about the vial.
That has a practical consequence: a sample can be 99% pure and be the wrong compound entirely, because purity says nothing about identity. It can be 99% pure, correctly identified, and hold half the milligrams the label claims, because purity says nothing about content. Water, residual solvent, salt counter-ion and endotoxin are all invisible to it.
Who is in this table. Every laboratory here that runs purity and identity work on a peptide sample. Cheapest published figure first.
| Laboratory | Method | One peptide | Turnaround | Country |
|---|---|---|---|---|
 Finnrick | Samples are received at a Texas facility and forwarded to commercial partner laboratories | Free (US$0) | Not published as a fixed window | United States |
 SR Biolabs | Liquid chromatography-mass spectrometry (LC-MS) as the core platform | US$150 per sample | 5 business days from receipt of the order | United States |
 Chromate | Qualitative and quantitative analysis by HPLC, which is the default for everything unless stated otherwise | US$180 per sample | Not published as a fixed window | United States |
 Prodigy Labs | RP-HPLC for purity, with retention-time identity at the entry tier | US$195 per sample | 5–7 business days, up to about 15 for a release panel | United States |
 TrustPointe Analytics | Assay and purity methods developed and validated under USP accuracy and precision requirements | US$200–$250 per sample | 3–5 business days, rush available | United States |
 Janoshik Analytical | Chromatography with mass-spectrometric detection for identity and composition | US$215–$450, per compound | Not published as a fixed window | Czech Republic |
 VialTests | HPLC-MS/MS for identity, area-% purity and net peptide content | CA$249.00 | About 5–10 business days after sample receipt | Canada |
 Accumark Labs | HPLC for identity, purity percentage and quantity per vial | US$250 per sample | 48–72 hours standard; 14 days for compendial sterility | United States |
 Maple Leaf Diagnostics | HPLC-UV/DAD coupled with mass spectrometry | CA$250 | 7–10 business days, next-day on priority | Canada |
 ARSI Canada | HPLC, UPLC, GC, GC-MS and ion chromatography | Quoted per job | Not published | Canada |
 Ethos Analytics | Validated methodologies under an ISO/IEC 17025 accredited quality system | Quoted per job | Not published as a fixed window; expedited service offered | United States |
 MZ Biolabs | HPLC with UV detection combined with mass spectrometry | Quoted per job | Not published | United States |
 SideChain Analytics | HPLC-MS/MS on a triple quadrupole, with a quantifier and a qualifier MRM transition reported for every analyte | Quoted per job | About 5 business days after sample receipt | Canada |
 Testides | HPLC-UV/DAD for purity as percentage area | In the order portal | Not published on the public portal | Canada and United States |
| Peptide Test Canada | HPLC for purity, reported as an exact percentage rather than a rounded estimate | CA$249 per sample | 5–7 business days, 2 business days on rush | Canada |
| BioRegen | UPLC | Quoted per job | Not published | United States |
 Forever Young Pharmacy | Reversed-phase HPLC (RP-HPLC) for purity quantification and identification | Published | Not published | United States |
 Freedom Diagnostics Testing | HPLC for purity | Quoted per job | 2–4 days average | United States |
 Peptide Test | Performed in Michigan by a partner laboratory specialising in QC testing of FDA-regulated pharmaceuticals | In the order portal | Not published | United States |
 ResolveMass Laboratories | High-resolution mass spectrometry, including LC-MS impurity profiling and direct-infusion identification of unknowns | Quoted per job | Not published | Canada |
 Vanguard Laboratory | LC-MS/MS and GC-MS | In the order portal | Not published | United States |
 Veritas Analytic | HPLC and UPLC | Quoted per job | 4–5 days standard | United States |
Every figure is read from the laboratory's own published information and links through to the full record. Prices are quoted in the currency each laboratory uses and are never converted.
The three measurements a good certificate carries
Identity, usually by mass spectrometry, answers whether the molecule is the one it should be by measuring molecular mass finely enough to separate closely related sequences. A certificate reporting purity without identity has established that a vial contains 99% of something unnamed.
Purity, usually by reversed-phase HPLC, answers what share of the detected material is the target. Net peptide content answers how many milligrams are actually there, quantified against a calibration curve rather than inferred from the fill.
Of the laboratories below, only some report all three. The ones that quantify content against an external calibration curve with an independent second-source standard are making the strongest claim available, and it is worth knowing which those are before comparing their price to a cheaper area-percent figure.
HPLC-UV and tandem MS are not the same purity
Purity by HPLC with ultraviolet detection reports what absorbed light at a chosen wavelength and eluted when expected. Purity by tandem mass spectrometry selects the intact peptide by mass, fragments it, and re-selects a specific fragment, reporting a quantifier and a qualifier transition.
The second survives things the first does not. A modification hiding under the main peak, or a closely eluting impurity, can pass a UV method and fail an MRM one. Both are legitimate; they are priced differently because they are different work, and a table that compares their prices without saying so is comparing two things.
What >99% means when a vendor prints it
Usually a release specification rather than a measurement: a threshold the seller set, not a figure a laboratory reported for the lot in your hand. Those are different claims and the distinction is the single most useful thing to hold on to when reading a product page.
A measured figure names a laboratory, carries a report identifier, states the lot it describes and gives the date and method. A document reporting 99% purity with no laboratory, no report number and no lot is not a certificate of analysis; it is a picture of one.
Common questions
What does 99% purity actually mean?
That the target peak accounted for at least 99% of the total peak area the detector integrated, under that method at that wavelength. It does not mean the remaining 1% was identified, and it says nothing about anything the method could not detect, including water, residual solvents and endotoxin.
Is purity the same as potency?
No, and conflating them is the most common error in this market. Purity is a proportion of what was detected. Potency, reported as net peptide content, is an absolute quantity in milligrams. A vial can be highly pure and substantially underfilled, and only a content measurement catches that.
How much does a purity test cost?
From US$150 for a qualitative identity and purity screen up to about CA$280 for identity, purity and quantified content together. The table above carries every published figure in the currency each laboratory quotes.
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Volta Peptides has no commercial relationship with any laboratory listed here and receives no referral fee. Listing is not endorsement, and details are the laboratories' own published claims rather than facts we have audited.