GLOSSARY
The analytical terms that appear on a Certificate of Analysis, in plain language.
Certificate of Analysis (COA)
A laboratory document recording the test results for one specific batch. It identifies the compound, states the measured purity, and names the testing laboratory and the date of analysis.
Batch
A single production and testing run. Analytical results describe the batch they were taken from and are not transferable to another batch.
Batch number
The identifier printed on the vial label that ties the vial to the certificate covering its batch.
Report code
A reference issued by the testing laboratory for a specific report. It allows the certificate to be checked directly with the laboratory rather than only with the supplier.
HPLC
High performance liquid chromatography. A separation technique that resolves the components of a sample and measures the relative amount of each. In peptide analysis it is the method behind the purity figure on a certificate.
LC-MS/MS
Liquid chromatography coupled with tandem mass spectrometry. Chromatography separates the sample and mass spectrometry measures molecular weight, which is used to confirm identity.
Purity
The proportion of total detected peak area attributed to the target compound, expressed as a percentage. It describes relative composition within what the method detects, not absolute mass.
Net peptide content
The mass of peptide in a vial, as distinct from the total mass of the lyophilised solid. The solid also contains counter-ions and residual moisture, so total vial weight is higher than peptide mass.
Lyophilisation
Freeze-drying. Water is removed from a frozen solution under vacuum, leaving a dry solid. Peptides are supplied lyophilised because the dry form is more stable in storage and transit than a solution.
Peptide
A chain of amino acids joined by peptide bonds. Chains are described as peptides at shorter lengths and as proteins at longer ones, with no single fixed boundary between the two.
Amino acid sequence
The order of amino acids in a peptide chain, conventionally written from the N-terminus to the C-terminus. The sequence defines the molecule.
Molecular weight
The mass of one molecule, reported in daltons. Because it is a property of the specific molecule, a measured value matching the expected value is consistent with the stated identity.
CAS number
A unique registry identifier assigned to a chemical substance by the Chemical Abstracts Service. It identifies a substance unambiguously across suppliers and literature.
Diluent
A liquid used to dissolve or dilute a solid in laboratory work. A diluent is not a peptide, so no purity or identity assay applies and no Certificate of Analysis is issued for it.
Third-party testing
Analysis performed by a laboratory independent of the supplier. The result does not rely on the supplier's own measurement.
Research use only
A supply condition stating that material is provided solely for lawful laboratory and analytical research. It is not for human consumption, therapeutic use, veterinary use, diagnostic use, or clinical application.
For research purposes only. Not for human consumption, therapeutic use, veterinary use, diagnostic use, or clinical application.