Research resources

A considered glossary

Certificate of analysis (COA)

A document in which a laboratory reports specified results for an identified sample. It supports only the questions its stated methods actually asked, and only for the sample it describes.

Lot (batch)

A quantity of material produced together and identified by a single code. The lot identifier is the join between a container and any document about it, which is why a missing or mismatched lot code breaks the link.

Chain of custody

The documented sequence of who held a sample, and when, between it being taken and being analysed. Most certificates for research materials do not include one, which limits how firmly a report can be tied to a specific container.

HPLC

High-performance liquid chromatography, a separation method used to estimate how much of the detected peptide-related material is the target. Reported purity is relative to what that particular method and its conditions detect.

Mass spectrometry (MS)

A method that measures mass-to-charge ratio and is used to ask whether observed material is consistent with the expected molecule. It addresses identity, which chromatographic purity presupposes rather than proves.