Guides

Plain-language guides to reading and checking laboratory documents. They explain what a report says and doesn’t say — not whether any product is safe to use.

• How to read a peptide Certificate of AnalysisWhat each part of a peptide COA means — identity, purity, quantity, dates, methods — what a COA can’t tell you, and a checklist to run through before you trust one.8 min read
• Purity, quantity and identity: what each number on a COA meansA 99% HPLC purity doesn’t mean 99% of the vial is the peptide. How purity, quantity (content) and identity differ, with a worked example and how much of a gap is normal.6 min read
• Signs a COA may be reused, edited or unreliableTen things worth checking on a laboratory report — reused chromatograms, dates out of order, QR codes that point elsewhere — and how to follow each up. A flag is a prompt to check, not proof.7 min read
• How to verify a Janoshik reportWhere to find the task number and unique key, how the QR code works, and what a match on the laboratory’s own verification page does and doesn’t prove.5 min read
• “Not tested”: endotoxin, sterility and what a missing test meansWhat endotoxin, sterility, heavy-metal and residual-solvent tests measure, why “not tested” is the absence of evidence rather than a pass, and how to read an incomplete COA.5 min read
• Can you trust a peptide COA? Five questions to ask of any reportA Certificate of Analysis is only as strong as who issued it, whether it can be verified, whether it matches your batch, and whether it holds together. Five questions to ask of any report.6 min read
• HPLC vs LC-MS: what each test tells you about a peptideHPLC-UV measures how much of what was detected is the main peak; LC-MS measures what the molecules are. What each can and can’t show, and why a COA usually needs both.5 min read
• What “research use only” means on a COA or label“Research use only” describes an intended use, not a quality standard. What the label does and doesn’t tell you about a product and its paperwork.4 min read
• Third-party lab or in-house COA: how much does it matter?An independent laboratory report is stronger evidence than a seller’s own — but who chooses the sample, who pays and what the lab’s accreditation covers still matter. How to weigh each.6 min read
• Batch and lot numbers: linking a COA to the vial you holdA COA describes a tested sample, and the batch label is what ties it to a product. How batch numbers work, where the link can break, and what to check on the vial and the report.5 min read
• How to read the HPLC chromatogram on a COARetention time, peak area, baseline and excluded peaks: what the chromatogram on a peptide COA shows, how purity is calculated from it, and what to look at before trusting the percentage.6 min read
• Reading a mass-spec result on a peptide COA: what [M+4H]4+ meansHow to read the charge states and m/z values on a peptide’s mass-spectrometry result, with a worked calculation you can check yourself.5 min read
• Was this COA PDF edited? What file properties can and can’t showProducer, creation and modification dates, fonts and embedded scripts: what a PDF’s properties can hint at, why they can’t prove anything either way, and the check that actually settles it.5 min read

Want to see it applied? Open the example report.