the paperwork can be perfect and the vial can still be light. weigh it
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#coa-reading 2026-05-25
Monday44 messages10 participantstimes are UTC
Highlights from this day
- gip_glp_gil — that is exactly the assumption the whole trade runs on 15:09
- assay_not_purity — depends entirely who made it. rough shape of what people have seen: 16:16
- deadspace — splitting this off, it deserves its own space 16:35
- deadspace — and trust is fine as long as you call it trust and not evidence 16:50
the related substances table is the interesting part. a row of "not detected" means they did not look hard
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does, still working it out
right so if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
tfa or acetate, how do i tell from the paperwork
follow up a certificate should name the method, the instrument, the column and the operator. most name none of those
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i asked GGPeps for the method and they sent it. that alone put them ahead of most
thats a tell
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
is a supplier certificate worth anything on its own
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
mixed fonts and inconsistent kerning in one document is worth a second look, i have it written down somewhere
the related substances table is the interesting part. a row of "not detected" means they did not look hard
not evidence on its own
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Testing queue: 3 submissions open, 36 awaiting dispatch.
unrelated but residual solvents matter more than people think for anything that went through a lot of purification steps
not detected means nothing
the retention time on this one is different from the last lot, problem
i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgwhy does everyone get so worked up about lot numbers
because without one the document cannot be attached to anything
a lot number is the join key. it is what lets you say this paper and this vial are the same event
no lot number and you have a nice chromatogram of something, somewhere, once
but the vendor sent it with my order so its mine surely
that is exactly the assumption the whole trade runs on
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i asked a vendor for the lot on my vial and they sent the same PDF back with a different number typed in the corner. same chromatogram, same integration table, same retention times
thats the giveaway. real reruns never land on identical retention times to two decimals
they land close. 12.41 vs 12.44 vs 12.39 across three injections is normal. identical to the hundredth across two separate lots weeks apart is not a coincidence, it is a copy
same-trace-two-lots-overlay.png
1440×900 · 288 KB · not retained in the public archive
overlaid them, they are pixel identical apart from the lot field
put that in #scam-watch too
what does a good lot format even look like
depends entirely who made it. rough shape of what people have seen:
| Source | Lot style seen | Traceable? |
|---|---|---|
| Bachem Holding | alphanumeric with a year block | yes, QA answers on it |
| Chinese Peptide Company | prefix + sequential | sometimes, if you are a real account |
| Wuhan Wansheng | prefix + date-coded | reseller-dependent |
| GGPeps | short numeric, reseller-assigned | usually no |
| anonymous reseller PDF | handwritten or absent | no |
and to be clear, reseller-assigned is not automatically dishonest. a reseller genuinely may not know the manufacturer lot
which is its own problem. if they do not know it, neither do you, so nobody can ever compare two of your orders
so a repeat order might be a completely different batch
might be a different synthesis route, let alone batch
this is why the batch-over-time tables in #test-results are more useful than any single COA
ok. so realistic best case for someone buying from a reseller
you keep your own records. lot if given, order date, vendor, and any test you paid for. after four or five orders you have a dataset nobody sold you
splitting this off, it deserves its own space
starting one tonight
if anyone wants a blank template ask in #archive-notes, a couple of people have shared theirs
worth saying: cpcbio and bachemholding are the two where i have personally had a lot number confirmed by someone who works there. everything else is trust
and trust is fine as long as you call it trust and not evidence
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