Home Blog #certificate-of-analysis
#certificate-of-analysis
10 pieces tagged certificate-of-analysis.
- Reading the paperworkWhy two laboratories get different numbers on the same lotAn HPLC purity figure is a method-dependent number. Where the differences between two reports on one lot come from, what measurement uncertainty is, and how to tell an expected gap from a real discrepancy.
- HandlingTFA salt or acetate salt: what the counter-ion changes about the vialWhere trifluoroacetate comes from, why it stays bound to basic residues, how much of a vial's mass it can be, what the literature reports about it in cell work, and what a certificate should say about salt form.
- Reading the paperworkSterility, metals and solvents: tests a purity certificate omitsWhat third-party tested actually covers. Purity, identity, sterility, endotoxin, elemental impurities, residual solvents and water are seven separate assays with seven separate standards, and a research certificate carries two or three of them.
- Reading the paperworkSeven ways a certificate of analysis misleadsRepresentative certificates, lot numbers that match nothing, in-house tests dressed as independent, purity without identity, stale dates and purity without net content: each pattern, and what a good certificate shows instead.
- Reading the paperworkIs the vial actually 5 mg? Fill weight, overfill and label accuracyHow a lyophilized vial gets its label mass, why that number is a target rather than a measurement, how a fill is checked, and how it interacts with net peptide content.
- Reading the paperworkA peptide paperwork glossaryThirty-six entries for the terms that appear on peptide certificates, labels and regulatory pages, each defined in one to three sentences from a primary source and linked to the piece that explains it.
- Reading the paperworkMass spectrometry identity: what a one-dalton match provesESI and MALDI in plain terms, why a peptide shows up at several m/z values at once, monoisotopic against average mass, and a worked example on a stocked fifteen-residue peptide from its PubChem entry.
- Sourcing and provenanceHow to vet a peptide vendor with documents, not with forumsA document-by-document checklist for judging a research peptide supplier: lot-specific certificates, identity as well as purity, net peptide content, a named manufacturer and a verifiable laboratory.
- Reading the paperworkChecking a peptide lab report: lookups, registers and ISO 17025A step-by-step way to check that a laboratory report is genuine, is about the sample it claims, and comes from a lab whose competence can be confirmed in a register the lab does not control.
- Reading the paperworkEndotoxin: what EU/mg means on a certificateWhat bacterial endotoxin is, how the LAL and recombinant Factor C methods detect it, why FDA's limit is a ratio rather than a figure in EU/mg, and why a research certificate usually stops short of it.
Nothing here is medical advice. Everything on this site is supplied for laboratory research use only.