Dr.NateNeph said:My vendor review relevant to certificates of analysis: ordered 5 times from my current compounder.
Bookmarking. The distinction being drawn above is the one nobody else makes.
From the other side of the consultation, briefly.
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: 14.3 minutes (consistent with semaglutide reference standard)
Peak purity: 99.0%
Related substances: 0.8% (single impurity at 8.1 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.58 (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.
MASHdoc_SA said: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:…
Second this.
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Shop Reference StandardsMASHdoc_SA said: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:…
Adding the part of the answer the thread has not reached. It helps to ask what evidence would change your mind before you look at any. If nothing would, the discussion is not about evidence, and it is better to say so early than to spend nine posts discovering it.
Correct me if the detail matters more than I have assumed.
One concrete data point for the thread. Worth stating the units and the reference range whenever you post a number here. A large fraction of the apparent disagreement in these threads is two people using different units and both being right.