log the lot number
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#test-results 2026-05-07
Thursday58 messages10 participantstimes are UTC
Highlights from this day
- maintenance_mo — if the vial has been through a bad transit you are testing the transit as much as the supplier 19:19
- back_from_away — i told Homopeptide about a result they would not have liked and they did not argue. credit where it is due 19:27
- salt_bridge — assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem 20:46
- salt_bridge — ok so i had a result i am fairly sure was a handling error on my side and i logged it as such 20:49
- underfill_uma — has a supplier ever disputed a result posted here post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later 22:17
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
whats the worst result anyone has logged and what happened next
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
log the boring results too. a channel that only records failures produces a false picture
thats not great
thats a fill problem
test it again
quantity testing is usually a separate line item and it is the one worth paying for
anyone had a result they think was a lab error rather than a bad vial
how much does sample handling on my end affect the number
log the boring ones
which lab
nice result
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the widest spread in my data is about 2.6 percentage points across five lots from one supplier
coming back after 1 months with a follow up result, where do i put it
weigh it first
is it worth testing if the vial has already been through a warm transit
update on the earlier thing a result without a lot number and a purchase date is an anecdote with a pdf attached, ymmv
my vial assayed under label but the purity was fine, which matters more
weigh the vial before you reconstitute. it costs nothing and catches the common failure
whats the lot
slightly off topic but i test roughly every tenth vial. it is a sampling strategy, not paranoia
attach the pdf
if the vial has been through a bad transit you are testing the transit as much as the supplier
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i told Homopeptide about a result they would not have liked and they did not argue. credit where it is due
coa-c-4402.pdf
1 page · 109 KB · not retained in the public archive
a supplier disputing a result is rare here and it has never gone well for the supplier
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update from 10 months ago: retested the same supplier, result came back better, logged both
one data point
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
is anyone tracking results over time in a way they would share
my result contradicts the supplier certificate, do i tell them
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do the results in this channel skew because people test when suspicious
certificate said 97.4 and the independent came back 98.1, is that a problem
genuine question a single sample tells you about a single vial. that is genuinely all it tells you
99.4 against a certificate of 96.8 is fine. the same supplier landing low four times in a row is a question
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
thats within range
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
do you test every order or sample it
20:30marrow.mod pinned a message to this channel
posting my VendorInvestigate result on lot B-0329, what do people make of it
selection bias
a point or two between the certificate and an independent result is inside what two labs disagree by
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
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ok so i had a result i am fairly sure was a handling error on my side and i logged it as such
vial-f-1330-front.png
900 × 1200 · 545 KB · not retained in the public archive
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
whats the underfill rate people are actually seeing
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
is a purity-only test worth the money if underfill is the common failure
how many lots do you need before you can say anything about a supplier
weigh the vial before you reconstitute. it costs nothing and catches the common failure
sorry to jump in underfill is more common than impurity. if you only test purity you are testing the less likely failure
[edited]for the archive how do you post a result so it is actually useful to somebody in a year
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does a bad result on one lot condemn the whole supplier
whats the lot
if you are testing to settle an argument you will not settle it with n of 1
has a supplier ever disputed a result posted here
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
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