Dr.ReproEndo said:Mass spectrometry confirmation for certificates of analysis: beyond HPLC purity, mass spec tells you the molecule's exact molecular weight.
Vendor quality matters when discussing certificates of analysis. I've tested my last 6 batches through Janoshik and purity has ranged from 98.9% to 100.7%. Consistency is key.
For anyone new: always request the COA, and consider independent verification. The $300 for a Janoshik test is worth the peace of mind.
Adding the numbers, since they settle part of this. Keep the original post as written when you update it, and add the correction underneath. An edited-away mistake is invisible to the next person who makes it.
One thing that is still open after Dr.ReproEndo’s answer:
Did your prescriber agree with that reading, and if not what was their objection?
PeptideDetective — Independent Peptide Analytics
Community-driven peptide testing and vendor rating platform. Transparent results. Unbiased analysis. Trusted by thousands.
View Resultskate.chem said:Keep the original post as written when you update it, and add the correction underneath.
I read this differently. The confidence in this thread is running ahead of the evidence, and I would rather the uncertainty were stated than smoothed over because it is unsatisfying.
kate.chem said:Keep the original post as written when you update it, and add the correction underneath.
Correct as far as it goes. The part it does not cover is what to do when the honest answer is "not enough data", which is more often than anyone likes.