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Sable Peptides

How to Read a Peptide Certificate of Analysis (COA)

How to Read a Peptide Certificate of Analysis (COA) is supplied for laboratory research only. Key facts are below; stored as lyophilised powder.

Last verified 12 Oct 2026.

A CoA for every lot; each vial carries a printed lot number that matches it. Ask with the lot number and we send it.

The short answer

A certificate of analysis (COA) ties one lot of material to its test results. Read it in this order: lot number, identity by mass, purity by HPLC, then the supporting details.

Research use only. Sable Peptides supplies laboratory reagents for in vitro and laboratory research by qualified people. Not a medicine. Not for human or veterinary use.

The short answer

A certificate of analysis (COA) ties one lot of material to its test results. Read it in this order: lot number, identity by mass, purity by HPLC, then the supporting details.

Field by field

| Field | What to look for | |---|---| | Product and lot | The name, sequence and a lot number that matches your vial | | Identity (MS) | The observed molecular mass against the theoretical mass. Electrospray spectra show several charge states (Fenn et al., 1989) | | Purity (HPLC) | The main peak area as a percentage, with column, gradient and detection wavelength (Mant et al., 2007) | | Appearance | For example "white lyophilised powder" | | Counter-ion | TFA or acetate. TFA residues can matter in cell-based work (Cornish et al., 1999) | | Net peptide content | Optional. Measured by amino acid analysis or nitrogen content (Rutherfurd & Gilani, 2009) | | Dates and signatory | Test date, retest date and the issuing laboratory |

Common misreadings

- Purity is not content. A 99% HPLC purity can come with roughly 70–90% net peptide by weight once counter-ions and water are counted. - A chromatogram without its method is hard to judge. Ask for the conditions. - A COA for a different lot says nothing about your vial.

At Sable

COAs are available for every batch on request. See the certificates page and the documentation request page.

- /education/certificates-not-on-file - /education/what-a-documentation-request-is - /learn/hplc-purity-explained

Sources

1. Mant CT et al.. HPLC analysis and purification of peptides. *Methods Mol Biol* 2007;386:3-55. PMID 18604941. PMC7119934. doi:10.1007/978-1-59745-430-8_1 2. Fenn JB et al.. Electrospray ionization for mass spectrometry of large biomolecules. *Science* 1989;246:64-71. PMID 2675315. doi:10.1126/science.2675315 3. Rutherfurd SM et al.. Amino acid analysis. *Curr Protoc Protein Sci* 2009;Chapter 11:11.9.1-11.9.37. PMID 19937719. doi:10.1002/0471140864.ps1109s58 4. Cornish J et al.. Trifluoroacetate, a contaminant in purified proteins, inhibits proliferation of osteoblasts and chondrocytes. *Am J Physiol* 1999;277:E779-83. PMID 10567002. doi:10.1152/ajpendo.1999.277.5.E779

*Last reviewed: 2026-10-10. Original Sable content; sources verified via PubMed E-utilities / Crossref / live HTTP checks on 2026-10-10.*

Last reviewed: 2026-10-10

How much does How to Read a Peptide Certificate of Analysis (COA) cost in the UK?

Frequently asked questions

What should every COA include?

Product name, lot number, test dates, HPLC purity with the method, observed versus expected mass, appearance, and the issuing laboratory.

Does 99% HPLC purity mean 99% peptide by weight?

No. HPLC purity is the main peak's share of UV-absorbing material. The net peptide content by weight is lower because of counter-ions and water.

How do I match a COA to my vial?

The lot number on the certificate must match the lot printed on the vial.

What if the observed mass does not match?

A mass outside the expected value (allowing for charge states and adducts) is a reason to query the lot before use.

Where do I request a Sable COA?

Through a documentation request; see the certificates page under /education.