Analytical Testing & Quality

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Analytical Testing & Quality

How research peptide identity and purity are verified, and how to read the supporting analytical documentation.

Racemisation and Chiral Purity in Synthetic Peptides

Where the wrong configuration comes from Every residue has to be activated before it can be joined to the chain that is being built, and activation has a side effect…

3 min read

Analytical Testing & Quality

Co-elution: When One Peak Is Two Compounds

Hydrophobicity is a coarse sorting rule A reversed-phase column ranks molecules by how strongly they prefer the stationary phase to the mobile one.

3 min read

Analytical Testing & Quality

System Suitability: What a Laboratory Checks Before Your Sample Is Run

A gate that runs before the sample does Ahead of any customer material reaching the injector…

3 min read

Analytical Testing & Quality

Deamidation in Peptides: the 0.98 Dalton Shift

An amide becomes an acid, and the mass barely moves Asparagine and glutamine each carry an amide group out on the side chain.

3 min read

Analytical Testing & Quality

Where Peptide Impurities Come From: Deletion, Truncation, Oxidation and Aggregation

A purity figure says how much of a sample is the target peptide. It says nothing about what the rest is, and the rest has identifiable origins.

5 min read

Analytical Testing & Quality

TFA and Acetate Counter-Ions: Why the Salt Form Changes Your Numbers

Free base is not how a synthetic peptide normally reaches anybody. What arrives is a salt, and the identity of that salt feeds into your concentration arithmetic and…

2 min read

Analytical Testing & Quality

Weighing Lyophilised Peptides: Hygroscopicity and Static

Putting an accurate mass on a lyophilized peptide is harder than the task appears. What makes it awkward is that the errors are systematic instead of random: they lean one way…

2 min read

Analytical Testing & Quality

Why Two Certificates of Analysis Can Disagree on Purity

Same batch, two laboratories, two different purity figures. No analyst blundered. The spread opened up because a purity percentage is the output of a procedure…

3 min read

Analytical Testing & Quality

Reading an HPLC Chromatogram: Shoulders, Baselines and Deletions

A bump riding on the side of the main peak, never quite resolving into anything of its own, is the most informative feature a chromatogram is likely to hand you.

3 min read

Analytical Testing & Quality

Water Content in Lyophilised Peptides and Why It Is Measured

Most of the water leaves a peptide preparation during freeze-drying. All of it does not. Whatever remains is simultaneously a mass appearing on your invoice and a variable acting…

2 min read

Analytical Testing & Quality

Endotoxin, Sterility and the Limits of “Research Grade”

Nothing is defined by the phrase "research grade." It is commercial description rather than a specification anyone can hold a supplier to…

2 min read

Analytical Testing & Quality

Third-Party vs In-House Testing: Reading Analytical Claims

Scroll any peptide supplier's homepage and "third-party tested" is almost certain to appear somewhere on it. As a phrase on its own it settles nothing.

5 min read

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Legal Disclaimer

The products offered by ExoLabz are intended solely for research purposes. These products are not for human consumption, are not intended for medical use, and have not been approved by the FDA for any therapeutic or diagnostic purpose. ExoLabz makes no claims regarding the safety, efficacy, or intended use of these products outside of a controlled research environment. By purchasing our products, you agree to use them strictly for scientific research and in compliance with all local laws and regulations.

Research-Grade Peptides and Compounds, Shipped from the USA | For Research Use Only.

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