Research-Peptide Documentation Glossary: COA, HPLC, LC-MS and More

Published 2026-10-20 · Last updated: 2026-10-20 · By: Index Peptides technical team

This glossary defines the documentation and analytical terms you will meet on a research-peptide certificate of analysis, on a vial label, and in dispatch records. It is a reference for reading paperwork, nothing more. Each entry explains what a field is and where it appears, so you can match a document to a vial with confidence.

Research use only. Not for human or animal consumption. Every entry below describes a documentation or analytical term. This glossary does not describe any use, effect or outcome of any compound.

Certificate and identity terms

• Certificate of Analysis (COA) — The analytical record for a single production run, listing the compound name, identifiers, the methods used, and the results. The anchor document for everything else. See what is a coa peptide.
• HPLC (High-Performance Liquid Chromatography) — The separation method used to report purity: how much of the sample is the main component, stated as an area percent. See what 99 percent hplc purity means.
• Area percent — The size of the target peak relative to everything else the detector records, expressed as a percentage. A relative figure, not an absolute weight.
• Chromatogram — The plotted output of an HPLC run, showing detected components as peaks along a time axis. See how to read hplc chromatogram.
• Retention time — The time a component takes to pass through the column and reach the detector. A consistent retention time helps characterise a peak.
• LC-MS / MS (Mass Spectrometry) — The method used to confirm identity: what the main component is, by measuring its mass. See lc ms identity confirmation explained.
• Expected vs detected mass — The theoretical mass calculated from the molecular formula (expected) compared against the mass the instrument measured (detected). Identity is the match between the two.
• Molecular weight — The fixed reference mass calculated from a compound's molecular formula. Independent and reproducible, so a detected mass can be checked against it.
• Molecular formula — The atom-count description of a compound, from which molecular weight is derived.
• CAS number — A registry identifier that ties a named compound to a single registered substance, used for cross-referencing.

Traceability and label terms

• Lot number / batch number — The identifier for one discrete production run. Often used interchangeably; it is the key linking a vial to its COA. See lot number vs batch number.
• Lot-to-label match — The check that the identifier printed on the vial equals the identifier on the certificate, character for character. The core traceability step.
• SKU — The stock identifier for a listed product, used to tie a listing to its batch records.
• Report date — The date the analytical record was produced, confirming results belong to that run rather than a reused template.
• Vial / lyophilised — The container and its physical form (freeze-dried solid). For handling guidance, see store lyophilised research peptides.
• Batch library — A held record of past lots with their certificates, purity figures, identity results, and report dates, so an identifier on a vial can be cross-referenced against documentation on file.

Independence and verification terms

• Third-party / independent lab — A laboratory with no commercial stake in the result, producing analysis separately from the supplier. See third party peptide testing labs.
• Supplier COA vs third-party COA — The distinction between in-house documentation and an independent report. Both have a place; they are not equivalent. See supplier coa vs third party.
• COA screenshot — An image of a certificate. A picture is not the same as a confirmed lot-to-label match against a current document. See coa screenshot not verification.

Logistics and record terms

• Dispatch after verification — The practice of confirming documentation is matched and on file before a SKU ships.
• Manual review — The held state for any SKU with missing or unmatched documentation, kept off-listing until records are complete.
• Batch-update signup — A way to be notified when new lots and their documentation are recorded.
• Invoice request — A request for a purchase record tied to a SKU and lot.

Reading a document with this glossary

Read a document field by field. Find the named method beside each result, confirm the lot or batch identifier is the same on the vial and the certificate, and check the report date. If a term on your paperwork is not listed here, the linked pages cover the most common ones in depth.

Research use only. Not for human or animal consumption. This page is reference documentation about analytical and record-keeping terms and does not describe any use, effect, benefit, dose, or outcome of any compound.

FAQ

What is a Certificate of Analysis (COA)?

A Certificate of Analysis is the analytical record for a single production run. It lists the compound name, identifiers such as the lot or batch number and CAS number, the methods used (typically HPLC for purity and LC-MS for identity), the results, and a report date. It is the anchor document that every other record and the vial label should agree with.

What is the difference between purity and identity?

Purity and identity are two separate measurements. Purity, usually from HPLC, reports how much of the sample is the main component as an area percent. Identity, from LC-MS, reports what that component is by matching the detected mass to the expected molecular weight. A certificate needs both, each tied to its named method, because a clean sample can still be the wrong compound.

Are lot number and batch number the same thing?

On research-peptide documentation they are usually used interchangeably. Both identify one discrete production run so a vial can be tied back to the certificate for that run. Some records combine them into one field, others print a batch number on the vial and a lot number on the certificate. What matters is that the identifier on the vial matches the identifier on the document, character for character.

What does lot-to-label matching mean?

Lot-to-label matching is the check that the lot or batch number printed on the vial label is identical to the one recorded on the certificate of analysis, the HPLC purity figure, and the LC-MS identity result. It confirms the documentation describes that specific vial rather than a different run, and is the core traceability step before a SKU is listed.

Why is a screenshot of a COA not the same as verification?

A screenshot is an image of a certificate, not a confirmed match. Verification means reading the lot or batch identifier on the vial, confirming it matches a current certificate held on file, and checking the method names, results, and report date all belong to that run. An image alone cannot confirm the document describes the vial in front of you.

Research use only. Not for human or animal consumption.