Dr.PulmRoch said:Reconstituted peptide stability data for certificates of analysis: I had Janoshik test my reconstituted vial at day 1, day 14, and day 28 stored in…
My HPLC chromatogram analysis for certificates of analysis — I sent my batch to Janoshik and here's what the results showed:
Main peak retention time: 15.2 minutes (consistent with semaglutide reference standard)
Peak purity: 99.4%
Related substances: 0.8% (single impurity at 9.5 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.6 (matches expected molecular weight)
This is a clean result. The mass spec confirmation is particularly important — it proves the molecule is actually semaglutide and not a substitution.
jennifer_SEA said:One addition: an unstated method makes a report close to uninterpretable.
Thank you — that is the clearest version of this I have read, and I have read a lot of them. I will report back once I have actually tried it.
Dr.PulmRoch said:Reconstituted peptide stability data for certificates of analysis: I had Janoshik test my reconstituted vial at day 1, day 14, and day 28 stored in…
Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 50 submitted tests:
- 82% tested at ≥98% purity
- 12% tested at 95-98% purity
- 6% tested at <95% purity (concerning)
The vendors with consistently high purity results are listed in the Vendor Directory. We update monthly based on new community submissions.
PeptideDetective — Independent Peptide Analytics
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View ResultsDr.SportsMedIN said:Two reports on the same product from two laboratories, four percentage points apart, and no method stated on either.
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: 99.5% purity, 0.3% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.