What the testing methods measure
HPLC and mass spectrometry answer different questions — purity and identity — and a quality report shows both with the underlying data.
✦ 2 min read · 2 sourcesWhat it is
High-Performance Liquid Chromatography (HPLC) separates the components of a sample and quantifies them, producing a purity percentage and a chromatogram. Mass spectrometry (MS) measures molecular weight to confirm the sample is the intended molecule. Purity and identity are distinct properties measured by distinct methods.
How it works
In HPLC, the main peak's area relative to the total indicates purity — commonly reported as a percentage, with quality material often cited around 98% or higher. MS ionizes the sample and measures mass-to-charge, letting an analyst confirm the observed molecular weight matches the expected value for the claimed peptide. A credible report shows the chromatogram and the mass-spec result, not just isolated numbers.
What the evidence shows
These are the standard analytical techniques described in pharmacopeial monographs and analytical-chemistry references for characterizing peptides. Regulatory guidance on synthetic peptides emphasizes impurity profiling by such methods, reflecting that a single headline number without supporting data is not meaningful.
Quick check
Four questions, ~60 seconds, with a sourced result.
The honest take
HPLC tells you how much; mass spec tells you what. You need both.
Status & safety
Educational overview of methods. Understanding the methods helps evaluate a report; it does not validate any specific product, and research material remains unverified for human use.
Summaries of published, third-party research for educational purposes. Not medical advice; not a claim of efficacy or safety for any use.
New, plain-language summaries as the literature develops. Educational only — no products, nothing for sale.
The three things that actually matter
Quality comes down to three verifiable things: is it the right molecule, how pure is it, and did an independent lab confirm both.
Read more →Independent labs vs in-house claims
Independent (third-party) testing is the single strongest quality signal because it removes the seller's conflict of interest.
Read more →What the document should actually contain
A trustworthy COA is specific and verifiable: it ties to your exact lot, names the methods, and shows the underlying chromatogram and mass-spec data.
Read more →How low-quality material is marketed
Most bad sources share the same tells: missing or generic documentation, no independent testing, and marketing that makes medical claims.
Read more →