kate.chem said:The provenance questions are more useful than the numbers.
COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis:
- No HPLC data: If there's no chromatography graph, it's not a real COA
- Exact 100% purity: Suspicious — real testing always shows slight variation
- No batch number: Can't trace back to specific production
- No endotoxin testing: For injectables, this is essential
- Template looks like it was made in Word: Professional labs have standardized formats
I have seen fake COAs that are literally photoshopped. Always verify independently if possible.
A narrower follow-up, since the general answer is now clear:
Whether a purity figure and a content figure can disagree without one of them being wrong?
dave_SLC said:COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis: No HPLC data: If there's no…
HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean:
- Purity %: Should be >97%. Below 95% is concerning.
- Retention time: Should match reference standard for the peptide
- Related substances: Degradation products should be <2% total
- Single impurity: No individual impurity should exceed 1%
My last batch: 99.7% purity, 0.3% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.
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Shop Reference StandardsClosing the loop on my own question.
Purity and content being different measurements was the piece I was missing. The vial was overfilled and pure, which is a very different problem from the one I thought I had.
PharmHunterJen said:HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…
Agreed, and mass spec answers a question purity does not: identity. High purity tells you one thing dominates the chromatogram, not that it is the molecule you ordered. A mass within about a dalton of expected is the identity check.