Every lot we release ships with a Certificate of Analysis, but the document is only useful if you know how to interpret it. This guide walks through the key fields you'll find on a Premier Aminos COA and what they mean for your research.
Purity by HPLC
High-performance liquid chromatography separates the target peptide from synthesis byproducts and degradation products. A purity of 99% means the main peak accounts for 99% of total peak area. For research use, anything ≥98% is generally considered high purity. We release lots at 98%+ and most lots test above 99%.
Identity by Mass Spectrometry
Mass spec confirms the molecular weight of the compound matches the theoretical value. This is the check that verifies you actually received the peptide you ordered — not a truncated or mis-synthesized sequence.
Water content and counterion
Lyophilized peptides retain some residual water and counterions (commonly acetate or TFA from purification). Water content above ~8% can affect accurate weighing. Our lots report water by Karl Fischer titration.
Endotoxin testing
For cell-based research, bacterial endotoxin can confound results even at low levels. Endotoxin is reported in EU/mg by LAL assay. Lots intended for sensitive applications test <0.05 EU/mg.
Why batch numbers matter
Always record the batch number on your vial. If you ever need to verify a result or request the full chromatogram, the batch number is how we pull the exact analytical record for your vial.
This article is provided for educational and research purposes only. All products sold by Premier Aminos are for laboratory research use only — not for human or animal consumption.
