The compound name

Obvious, until it is not. Research compounds accumulate names: catalogue codes, scientific names, registry numbers. The certificate should use precise nomenclature that matches the product listing, ideally with a CAS registry number where one exists. Vague or mismatched naming is the first sign of a supplier who does not control their documentation.

The batch or lot number

One of the most important fields on the page. A certificate describes one specific production run, not a product in general. The batch number on the certificate must match the batch number on the vial in your hand; that match is what connects your physical material to the analytical results. A certificate without a batch number, or one reused across different batches, describes intentions rather than contents.

The purity figure, and what HPLC actually measures

Purity on a peptide certificate is normally measured by high-performance liquid chromatography. The method is worth understanding because it turns the purity percentage from marketing into measurement. A dissolved sample is pushed under pressure through a column packed with fine material. Different molecules travel through at different speeds and emerge, or elute, at characteristic times. A detector records what comes out, producing a chart called a chromatogram: the target peptide appears as the dominant peak, and anything else in the vial appears as smaller peaks. Purity is calculated from peak areas. A figure of 99% means the main peak accounts for 99% of the total measured peak area under that method’s conditions. Two qualifications matter to researchers. The result is method-dependent: it reflects what the column can separate and the detector can see, so it is not the same thing as absolute chemical purity of everything in the vial, and impurities the method cannot detect will not appear in the figure. And it is batch-specific: a quantitative result from one run of one batch, which is why it cannot honestly be copied from one batch’s certificate to another’s.

Identity confirmation

Purity tells you how much of the main component is present; it does not tell you the main component is the right molecule. That is what identity testing is for, usually mass spectrometry, which measures molecular weight. The measured weight should match the compound’s theoretical weight. A certificate with a purity figure but no identity confirmation is only half a certificate.

The supporting fields

Appearance describes what should be in the vial, typically a white lyophilised powder or cake, a quick physical check before use. Synthesis or analysis dates and a retest or expiry date place the batch in time. Storage conditions state how the material should be kept, and are worth following exactly, because they reflect the form the stability data was generated in.

The red flags

The same certificate appearing on different batches. Purity figures that are suspiciously round, stated without a method, or identical across every product a supplier sells. Certificates only available after purchase or behind a login. No batch number, no identity test, no named method. None of these prove a product is bad; all of them prove you cannot know either way, and in research, not knowing is the failure.

Every Proba Research product page links to its certificate of analysis before you buy, and the figure on the certificate is the figure that counts.