Glossary

The laboratory's own identifier for a submitted sample. It appears on the certificate beside the certificate number and ties the report to the physical sample received.

Molecules of a peptide clumping together instead of changing chemically. Driven by concentration, shaking, freeze-thaw cycles and hydrophobic sequences. Once it happens, it is usually permanent.

How HPLC purity is reported: the target peak's area as a share of all peptide-related peaks in the chromatogram. It describes the peptide part of the powder, not the whole powder.

Sterile water with 0.9 percent benzyl alcohol added so a vial can be opened more than once. The preservative slows bacterial growth in the water and does nothing for the peptide.

The preservative in bacteriostatic water, at 9 mg per mL. It slows bacterial growth but does not sterilize, and it is compatible with the large majority of freeze-dried peptides.

A very short synthetic peptide, typically two to four residues, from the Khavinson series and related work. Grouped here by structure like every other class. The class reference lists the series by sequence.

Two or more compounds in one vial, with the amount of each stated on the label and on the certificate. A blend certificate confirms each compound separately.

A registry number assigned by the Chemical Abstracts Service to a specific substance. Where a compound has one, it is stated on the specification.

The lab report for a tested sample: identity, purity, net content and other measured results, with the lab named and its report number stated. Ours are on each product page.

The trace an HPLC run produces: detector response against time. The target peptide is one peak; anything else the detector saw is another.

Keeping material within a temperature range from shipping to arrival. Freeze-dried peptide handles ordinary shipping temperatures, and our boxes are not refrigerated in transit.

Peptide mass divided by liquid volume. For example, 10 mg in 2 mL gives 5 mg/mL. Worked from peptide mass, corrected for net peptide content where the certificate reports it.

The ion, usually acetate or trifluoroacetate, that balances the charge of a peptide in its solid form. Part of the powder's weight, not part of the peptide.

A breakdown route in which asparagine or glutamine loses an amide group. It needs water, so it barely runs in a dry powder and runs freely in solution.

Fragments of the outer membrane of gram-negative bacteria, which cause fever even when the bacteria are dead. Measured by a LAL or recombinant factor C test, not by a sterility test.

An immunoassay run by the laboratory at a stated cutoff, reported as detected or not detected. Present on every certificate filed here.

High performance liquid chromatography. Separates the components of a sample and reports what share is the target compound. It answers how much, not what.

The peptide backbone breaking apart by reaction with water. A dry powder is almost immune to it. A solution is not.

Confirmation that the compound in the vial is the one named on the label. On our certificates, by HPLC retention time against a reference standard. On others, often by mass spectrometry.

The international standard for testing labs. Accreditation means an independent body has audited the lab's methods and quality system.

One production batch of a compound. Some suppliers print a lot number on every vial so it can be matched to a certificate for that batch.

Freeze-drying. The material is frozen and the water pulled out under vacuum, leaving a dry cake that keeps far better in storage and transit than a solution.

The porous solid left in the vial after freeze-drying. How it looks is a quality check: intact and dry is right; collapsed, melted or discolored is not.

Measures the mass of a molecule and compares it with the mass the sequence predicts. Answers what, not how much. Not the identity method on the certificates filed here.

The mass of one molecule of the compound, stated in grams per mole on the specification. Used with the sequence to check identity results.

The weight of actual peptide in the vial, as opposed to the labeled powder weight, which also includes water, counterion and residual salts. A vial can be 99 percent pure and 78 percent peptide.

A breakdown route that hits methionine, cysteine and tryptophan in particular. Driven by light, trace metals and peroxide in buffers.

On these certificates, the HPLC area percent of the target peptide relative to all peptide-related peaks. It is not net content and it is not sterility.

Dissolving freeze-dried powder in liquid, usually bacteriostatic water. Run it down the inside of the vial, not onto the cake, and never shake.

A sample of known identity the lab runs alongside the submitted sample. A matching retention time confirms identity.

The condition every item here is sold under. Not a drug, food, cosmetic or supplement, not for human or veterinary use, and not offered for any such use.

How long a compound takes to travel through the HPLC column. It is characteristic of the compound under fixed conditions, and comparing it to a reference standard confirms identity.

A GHS-format document describing the hazard class of a compound in general terms. Added next to the compound's certificate as we receive it from the supplier.

The order of amino acid residues in a peptide, written from the N-terminus. Stated on the specification where known.

The method by which research peptides are made: the chain is built one residue at a time on a resin, then cleaved and purified by preparative HPLC.

Whether and how readily a peptide dissolves in a given liquid. Sequence and pH decide it. The solubility guide covers what to do when a cake will not dissolve.

How long a peptide keeps its identity and purity under a stated condition. Years for a sealed dry powder at minus 20 C. Days to weeks for a solution.

The absence of living microorganisms, tested by culture. A different question from endotoxin, and not part of the release standard for freeze-dried research material.

Testing by a lab independent of the seller, named on the certificate with its own report number. The alternative is an in-house or unnamed report, which the guides tell you not to accept.

Checking a certificate with the lab that issued it, using the report number or code printed on it.