Testing
How our batch testing and documentation works
What HPLC and mass spectrometry actually measure, and how to read a certificate of analysis.
What a certificate of analysis contains
A certificate of analysis is the analytical record for one production run of one compound. Ours record the compound name and vial size, the lot number, the date the assay was performed, the purity percentage returned by high-performance liquid chromatography, and the identity confirmation from mass spectrometry. Together those fields answer the two questions any assay result depends on: is this the right molecule, and how much of what is in the vial is actually that molecule?
The lot number is the link between the paper and the glass. It is printed on the vial label and on the certificate, and searching it here returns the record for the exact material you hold. If a study runs across several months and several reorders, keeping the lot numbers with your data lets you attribute any step change in results to a batch boundary rather than to your protocol.
Why purity figures vary between batches
Solid-phase peptide synthesis is a repeated cycle: deprotect the terminal residue, couple the next one, wash, repeat. Each cycle runs at a coupling efficiency slightly below one hundred percent, and the shortfall compounds. A thirty-residue sequence at 99.5% per-cycle efficiency finishes at roughly 86% full-length material before purification; the same sequence at 99% finishes near 74%. Preparative HPLC then removes most of the shortfall, but the starting point determines how much work purification has to do and how much of the target is lost with it.
Longer and more hydrophobic sequences are harder. Chains that fold or aggregate on the resin bury the reactive terminus and slow coupling, producing deletion sequences that differ from the target by a single residue and elute very close to it. That is why a 50mg tripeptide can be certified at 99.4% while a longer analogue from the same facility comes in at 99.0% — the numbers reflect sequence difficulty, not inconsistent standards.
We publish the figure the run produced rather than rounding to a marketing number. A batch that does not clear our release threshold is not relabelled or blended into a passing lot; it is not sold.
Independent testing and what 'third party' means
Assays are performed by an analytical laboratory with no commercial interest in the result, working from samples drawn from the finished, filled lot rather than from pre-production material. That distinction matters: testing a synthesis batch before filling says nothing about what happened during lyophilisation and vialling, which is where oxidation and moisture ingress occur.
Certificates are uploaded before the batch is listed, not after the first order. If a listing is live, its analytical record is already searchable above. Where a study or an institutional purchasing process needs the underlying chromatogram rather than the summary certificate, quote the lot number in an enquiry and we will send the trace.
Using certificates in your own documentation
For reproducibility, record the compound, vial size, lot number and certified purity alongside your method rather than the supplier name alone. Reviewers and colleagues repeating the work can then match material precisely, and any discrepancy between runs can be traced to a specific analytical record rather than argued about in the abstract.
All compounds referenced in this library are supplied for in-vitro laboratory research by qualified personnel. They are not medicines and are not for human or veterinary consumption.