WXT is the only vendor whose COAs reliably include water content and i think that is the tell
1,100-odd COAs in my folder structure. Sorted by vendor, then compound, then batch. I do this instead of having hobbies.
Here is a pattern I did not expect: water content — Karl Fischer or loss on drying — appears on almost every WXT document I have, and almost nobody else's. Nobody asks for it. It is not required. It does not make the purity number look better.
Which is precisely why I think it is informative. A vendor that reports a field with no marketing upside is a vendor whose QC culture generates the field as a matter of course, rather than assembling a document for you.
BCH is the other one that does it consistently. Both of those are 2002/2003 establishment dates and both feel like they came from a manufacturing background rather than a shop background.
best — the order this archive was captured in
Yes. And the reason it matters beyond signalling: residual moisture eats directly into your net peptide content and no purity figure will ever show you that.
A vial with 4% water is carrying 4% less of what you paid for, and the chromatographic purity can still be a perfectly honest 99% because purity is a ratio and water does not absorb at 214nm. Two completely different questions, one document.
this is the bit i should have led with instead of burying it in paragraph three. fixing that in my head for next time.
i genuinely did not know water was invisible to the detector. that reframes about half of what i thought i understood.
UV sees things that absorb UV. water does not. salts mostly do not. that one sentence explains most of the confusion in this community.
saving this comment specifically
it is also the second section of the COA wiki page, which nobody reads until after they have been confused once. that is fine, that is how wikis work.
Cross-posting this into the c/coa wiki as a worked example of "fields nobody asks for". Good post.
Also using this to repeat the ask: when you post a COA, post the whole page. Water content is at the bottom of most documents and it is the first thing a crop removes.
BCH and WXT both being pre-2005 entities is not a coincidence in my view. The documentation habits of a contract manufacturer are different from those of a reseller and it shows up in the boring fields.
both establishment dates check out against filings, for what it is worth. i re-verified WXT in 2024 and BCH in 2023.
counterpoint, mildly: SWB has never given anyone a straight answer about their method and their material has still been fine every single time. documentation habits correlate with quality, they do not determine it.
agreed and that is a fair check on my argument. correlation not causation, n of about eight vendors. edit: SWB is 4.4 on our own directory largely because of exactly that gap, so the community has already priced it in.
the field i actually want and never get is amino acid analysis. it catches the frauds that HPLC waves through.
tl;dr — a vendor reporting a number that does not flatter them is telling you something about their process. WXT and BCH do it, most do not.
- 1Yes. And the reason it matters beyond signalling: residual moisture eats…6 comments in this branch · started by u/karl_fischer_kev