Know your documentation.

How to Read a Certificate of Analysis

A certificate of analysis (COA) is the paperwork that turns a claim into something checkable. For research material, it is the difference between "trust us" and "here is the evidence." Knowing how to read one lets you evaluate material on its documentation rather than its marketing.

Identity: is it the right molecule?

The identity section reports whether the material matches the compound named on the label. It typically references a method — often a mass-based technique — and confirms that the measured result aligns with the expected value for that molecule. Identity and purity are separate questions: a sample can be correctly identified yet still contain impurities, so treat these sections independently.

Purity: how much of it is the target?

Purity is usually expressed as a percentage representing the target compound's share of the total, most often derived from a chromatographic separation. A single figure is useful, but it is only meaningful alongside the method that produced it. A well-formed COA states the method next to the number so you can interpret the value in context rather than at face value.

Method: how was it measured?

The method entries name the analytical techniques used. You do not need to be an analyst to benefit — simply seeing that a specific, named method backs each result tells you the figures were generated by a defined process rather than asserted.

Batch traceability: does it match what you hold?

Finally, a COA should carry a batch number and a test date, tying the document to a specific production lot. When the batch number on your material matches the one on the certificate, the documentation actually describes what is in your hand. If those do not match, the certificate describes a different batch.

The short version: check that identity and purity are reported separately, each with a named method, and that the batch number and date correspond to the exact material you received.

Understanding Peptide Purity Testing

"Purity" sounds like a single, simple number. In practice, it is the output of a measurement process, and understanding that process is what lets you read a purity figure critically rather than accepting it blindly.

Separation by RP-HPLC

Reversed-phase high-performance liquid chromatography (RP-HPLC) is a common way to assess purity. A dissolved sample is pushed through a column whose material interacts differently with different substances, so components emerge at different times. The result is a chromatogram — a series of peaks. The target compound produces a main peak; related substances show up as smaller peaks. Purity is commonly reported as the main peak's share of the total peak area.

Identity by mass spectrometry

Mass spectrometry (MS), often coupled with a separation step as LC-MS, measures the mass-to-charge ratio of a compound's ions. Comparing the measured mass to the expected value supports the material's identity. MS answers a different question than HPLC: not "how much is the target?" but "is this the molecule it claims to be?"

Why one number never tells the whole story

A purity percentage depends on the method, the conditions, and what the method can and cannot detect. Two figures generated by different methods are not directly comparable, and a high number does not automatically describe every attribute of a sample. That is why reputable documentation reports purity together with the method behind it, and reports identity separately.

• Read the method, not just the percentage.
• Treat identity and purity as distinct results.
• Be cautious comparing figures across different methods or labs.

The takeaway: a purity number is a summary of a measurement, not an absolute property. The more you understand the measurement, the more useful the number becomes.

Proper Storage Considerations for Research Peptides

Keeping research material stable is largely about controlling its environment. The general principles below concern storage and stability of laboratory material — they are not instructions for preparing or using anything, and they do not replace the guidance that accompanies a specific batch.

Lyophilized material

Many research peptides are supplied lyophilized — freeze-dried into a dry powder. In this form they are generally more stable than in solution, which is why they are shipped and stored dry. Keeping lyophilate cold, dry, and sealed helps preserve it over time.

Temperature and the cold chain

Temperature is one of the biggest factors in stability. Cooler storage generally slows degradation, and some material benefits from cold-chain handling during transit. Repeated warming and cooling is worth avoiding, since temperature swings can be harder on material than steady cold storage. Whether a given order ships with temperature-controlled packaging is not yet published; see the shipping policy.

Light and moisture

Light and moisture can also affect stability. Storing material protected from light and sealed against humidity reduces avoidable exposure. Letting a sealed container reach a stable temperature before opening can help limit condensation.

Documentation and dating

Good storage practice pairs with good record-keeping: noting what you have, its batch number, and when it was received makes it far easier to track material against its documentation. The batch-specific notes that accompany a certificate are the authoritative reference for a given material.

In short: cold, dry, dark, sealed, and stable — plus records that tie material back to its batch. General stability principles, not use instructions.