A Certificate of Analysis from a reputable peptide supplier includes two distinct analytical results: HPLC purity and mass spectrometry confirmation. These tests answer different questions. A single number without the other is incomplete verification.
VerificationHPLC: what it measures
High-Performance Liquid Chromatography separates the components of a sample by pushing it through a column under high pressure. Different molecules travel at different speeds and exit at different times. The instrument records a peak for each component. The size of your target compound’s peak relative to everything else gives you the purity percentage.
HPLC tells you what fraction of the sample is your compound. A 99.2% result means 99.2% of the detected material had the expected retention time. It does not confirm what that material actually is.
VerificationMass spectrometry: what it confirms
Mass spectrometry measures molecular weight. The instrument ionizes the sample and measures the mass-to-charge ratio of the resulting fragments. The output is a spectrum that identifies the molecule by its exact mass and fragmentation pattern.
MS confirms identity. A compound can show high HPLC purity while being the wrong molecule entirely. HPLC would not catch a substitution if the substitute compound eluted at the same time. Mass spec catches it because the molecular weight is different.
Why you need both
HPLC alone tells you something pure arrived. MS alone tells you the right molecule arrived. Together, they confirm you received the correct compound at the stated purity. Reputable labs run both as standard. Suppliers providing only one result are giving you half the picture.
Every Vantage Aminos lot is run on HPLC-UV and mass spectrometry by a contract analytical laboratory in the United States, commissioned by the manufacturer. Results appear on the batch Certificate of Analysis published on each product page, alongside the chromatogram and mass spectrum the measurements are read from.
What the numbers should look like
Research-grade purity starts at 98%. Pharmaceutical-grade runs 99%+. For most peptide research applications, 98-99.5% is appropriate material. Below 95% is a concern worth raising with your supplier before use. The mass spec result should match the expected molecular weight of the compound within 0.1-0.2 Da for a clean result.
- HPLC + MS tested, every batch
- U.S. synthesized
- Batch COA on the product page