Glossary · 4 min read · Updated September 27, 2026
Research Peptide Glossary
Short definitions of the terms that appear on peptide product pages and Certificates of Analysis, from lyophilized and counter-ion to HPLC, MS and net peptide content.
Terms
- Acetate salt: a common counter-ion form of synthetic peptides (for example sermorelin acetate); the acetate contributes to the weight of the powder.
- Batch (lot): one production run. Testing results apply to a specific batch.
- Certificate of Analysis (COA): a batch-specific record of the tests performed and their results.
- Counter-ion: an ion paired with a charged peptide in the solid form, such as acetate or trifluoroacetate (TFA).
- HPLC: high-performance liquid chromatography, the standard method for measuring peptide purity.
- Lyophilized: freeze-dried. Water is removed under vacuum at low temperature, leaving a dry powder or "cake" that is more stable in storage than a solution.
- Mass spectrometry (MS): a method that measures molecular mass to confirm a compound's identity.
- Net peptide content: the percentage of the powder's weight that is the peptide itself, excluding counter-ions and water.
- Purity: the share of the analytical signal (usually HPLC peak area) belonging to the target compound.
- Research use only (RUO): sold for laboratory research, not for human or animal use, and not intended to diagnose, treat, cure or prevent disease.
- SKU: a stock-keeping unit, the code for one product in one size.
Educational content for laboratory researchers. Renuvia Labs products are for research use only and are not for human or animal consumption.