Twelve things a real certificate has, and what their absence means

Certificates exist because a manufacturer selling a material to a purchaser who cannot test it needs a way to transfer information about quality along with the goods, and because somebody eventually needs to be able to reconstruct, months later, what was known about a particular batch at the moment it was released. The second purpose is the one that shapes the document, and it is the one the research-chemical version of the form has almost entirely lost.

A certificate is a document, not a test

The confusion at the root of almost every dispute about certificates is a category error. A certificate of analysis is not a measurement. It is a record asserting that measurements were made, by named methods, on identified material, on a stated date, with stated outcomes, and that somebody reviewed and released the batch on that basis. The measurements exist elsewhere: in instrument data files, in analyst notebooks, in a laboratory information system. The certificate is the summary that travels with the goods.

This distinction has a practical consequence. When the Journal wants to know whether a purity figure is sound, we do not scrutinise the certificate; we ask for the underlying laboratory report and, where possible, the chromatogram. The certificate can only tell us what somebody concluded. The chromatogram tells us what the instrument saw, and the two are separated by decisions about integration, thresholds and reporting that the certificate does not record.

It follows that a certificate’s value is almost entirely a function of whether it can be traced back to that underlying evidence. A document with a batch number, a date, a named method and a named analyst is checkable in principle even if nobody ever checks it. A document with a percentage and a logo is not checkable by anyone, including the company that issued it, and the difference between those two situations is invisible to a buyer who reads only the number.

The header block: identifying the object

The top of a certificate answers the question, what is this document about. A complete header names the product, gives a catalogue or item number, gives the batch or lot number, states the quantity or fill weight, names the manufacturer and the site, and identifies the customer or order where applicable. Some add a chemical name, a sequence in single-letter code, a molecular formula and a molecular weight, all of which are useful because they let a reader check the theoretical values used elsewhere on the page.

The sequence in particular is worth insisting on. A certificate that prints the one-letter sequence has given a reader the means to calculate the expected mass independently, and therefore to check the identity line. Two of the twenty companies in the Journal’s dossier programme do this as standard. It costs nothing and it converts one line of the document from an assertion into a verifiable claim.

What a header should never do is identify the product only by a trade name. A vial described as a proprietary blend with no chemical identity, no formula and no sequence cannot be checked against anything, and a certificate for such a product is a document about a name. This is a documentary observation rather than an accusation, and the remedy is trivial: print the sequence.

The lines nobody reads: appearance and solubility

Near the top of most test tables sit two entries that buyers skip and chemists do not: appearance and solubility. Appearance is reported as something like “white to off-white lyophilised powder”, and it is a real test with real discriminating power. A peptide cake that is yellow, or grey, or that has collapsed into a glassy plug rather than a light lyophilised mass, is telling you something about the drying cycle, about oxidation, or about a temperature excursion in transit.

Solubility is similarly underrated. A specification reading “clear, colourless solution on reconstitution in water at 1 mg/mL” establishes that the material dissolves at the concentration a user will need, without haze, and haze on reconstitution is a genuine finding: it can indicate aggregation, incomplete removal of a protecting group, or particulate contamination. It is also the only test on most certificates that a buyer can repeat at home.

The reason to press on these lines is that they are cheap, they are already on the form, and they degrade in a way the purity figure does not capture. A certificate reporting a white powder for material that arrives faintly yellow has not been falsified. It has been overtaken by events, which is exactly what a certificate with an eleven-month-old date of analysis should be expected to be.

Water, counter-ion and the mass in the vial

A lyophilised peptide is not pure peptide even when it is chromatographically pure. It is a salt, usually of trifluoroacetic or acetic acid, containing residual water that a hygroscopic powder acquires readily, and sometimes residual solvent from purification. Three lines on a certificate address this and they are usually absent: water content, counter-ion identity and content, and residual solvent.

Water is determined by Karl Fischer titration or by loss on drying, and the pharmacopoeial methods for it are old, settled and inexpensive.¹ A peptide containing eight per cent water by mass contains eight per cent less peptide than its label implies, and the figure is not stable: it depends on how the vial was stoppered and how long it has been open. Counter-ion content is a larger contribution still for basic peptides purified in trifluoroacetic acid, where the counter-ion fraction can reach ten to twenty per cent of total mass.²

Put these together and the practical statement is the one this department repeats: the nominal mass on a research vial is an upper bound on the peptide it contains, not a value. A certificate that reports purity and is silent on water and counter-ion has told you the material is clean and nothing at all about how much of it there is.

The footer: dates, signatures and the release statement

The bottom of a certificate carries the dates, the signatures and any boilerplate. A complete footer gives the date of manufacture, the date of analysis, and either a retest date or an expiry date with the convention named. It gives the name and role of the person who performed or compiled the testing, and separately of the person who reviewed and approved it. It states the storage conditions under which the stated properties hold. And it states, in a research-chemical context, the research-use-only restriction.

The two-signature convention is worth explaining because its absence is so universal here that its purpose is forgotten. Separating performance from approval is a control against a single person’s error or judgement determining a release. It is cheap, it requires no equipment, and it is the ordinary practice in every regulated laboratory. Its function is not ceremonial: it means that when a document turns out to be wrong, there is a record of who reviewed it and on what basis.

What the footer should not carry is a signature rendered as a reused image with no accompanying name. That is not evidence of anything improper on its own — scanned signature blocks are common in legitimate commerce — but it removes the one piece of information the block exists to supply, which is the identity of a person who can be asked.

What remains genuinely absent from this market is any documentation of what happens to a vial between the date of analysis and the day it is opened. Every certificate is a snapshot at manufacture; nothing records the four months in transit and storage that follow. Until somebody prices a cheap release-and-receipt check, the honest statement about any research vial is that its purity was measured once, some time ago, by a method that may not be stated.