Peptide Sciences quality was declining BEFORE shutdown — PeptideMeter data

labquiet_amy said:

HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…

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: 16.4 minutes (consistent with semaglutide reference standard)
Peak purity: 98.8%
Related substances: 0.6% (single impurity at 10.4 minutes — likely a synthesis intermediate)
Mass spec: m/z 4113.5 (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.

labquiet_amy said:

HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…

No disagreement, though the timescale matters more than the mechanism here. Most of what looks like a difference in kind turns out to be a difference in how long somebody waited.

Correct me if the detail matters more than I have assumed.

labquiet_amy said:

HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean: Purity %: Should be…

Thank you for spelling out the reasoning rather than just the conclusion.

From the other side of the consultation, briefly. Start from the measurement rather than the conclusion. Almost every disagreement here turns out to be two people measuring different things and comparing the numbers anyway.

That is the short version; the long version is somebody else's post.

Dr.GutHealth said:

Start from the measurement rather than the conclusion.

Second this. I had assumed I was the exception until I read this.