How to read a peptide certificate of analysis
What each section of a peptide CoA actually proves — HPLC purity, mass-spec identity, water and counter-ion content — and how to match a certificate to the vial in your hand.
8 min readResearch Notes
Technical notes on handling, analysing and documenting reference-grade compounds — written for people working at a bench. For laboratory research use only.
Quality
Endotoxin in peptide reference material and why cell assays care
Bacterial endotoxin survives sterile filtration and autoclaving, and provokes responses in cultured cells at very low concentrations. What LAL testing measures and when it matters.
6 min readWhat “research use only” actually means
The regulatory meaning of research-use-only designation, how it differs from clinical or pharmaceutical grade material, and what it obliges a purchaser to do.
5 min readAnalysis
HPLC and mass spectrometry: what each assay actually proves
Reversed-phase HPLC measures how much of one thing is present. Mass spectrometry establishes what that thing is. Neither substitutes for the other on a peptide certificate.
7 min readNet peptide content, counter-ions, and why a milligram isn't a milligram
Lyophilised peptide powder contains water and counter-ion salt alongside the compound. Net peptide content, not HPLC purity, determines how much material a vial really holds.
7 min readHow peptides degrade: oxidation, deamidation, hydrolysis and aggregation
The four routes by which peptide reference material loses integrity, which sequences are vulnerable to each, and what the resulting mass shifts look like on an assay.
8 min readHandling
Storing lyophilised peptides: temperature, moisture, and light
Lyophilised peptides are stable for long periods when kept cold, dry and dark. Practical storage guidance for reference material held in a laboratory.
6 min readReconstituting lyophilised peptides for in-vitro work
Preparing a stock solution from lyophilised reference material: solvent choice, concentration arithmetic, avoiding foaming and adsorptive loss, and aliquoting.
8 min readPeptide solubility: predicting it from sequence
How charge, hydrophobicity and secondary structure determine whether a peptide dissolves in water, needs dilute acid or base, or requires an organic co-solvent.
7 min readAliquoting, freeze-thaw cycles, and adsorptive loss
Why repeated freezing degrades peptides in solution, how much material dilute solutions lose to container walls, and how to size aliquots so neither problem compounds.
6 min readCatalog
Operations
Receiving and inspecting a peptide shipment
A short inbound checklist: what to verify on arrival, what a collapsed cake or broken seal tells you, and what to record before material enters inventory.
5 min readDocumentation and traceability for reference material
What to record about a peptide lot so results stay interpretable months later: inventory fields, preparation records, and tying data back to a specific vial.
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