is anyone tracking results over time in a way they would share
#test-results 2025-06-30
Monday49 messages10 participantstimes are UTC
Highlights from this day
- HPLC_Hank — post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later 17:03
- knees_first — one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally 17:12
- bea_reconstitutes — a supplier disputing a result is rare here and it has never gone well for the supplier 18:33
- split_dose_sam — a point or two between the certificate and an independent result is inside what two labs disagree by 18:36
thats not great
[edited]post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
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one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
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quantity testing is usually a separate line item and it is the one worth paying for, not advice obviously
does a bad result on one lot condemn the whole supplier
when did you buy it
a single sample tells you about a single vial. that is genuinely all it tells you
test it again
99.4 against a certificate of 97.4 is fine. the same supplier landing low four times in a row is a question, we shall see
how do you post a result so it is actually useful to somebody in a year
do you test every order or sample it
attach the pdf
nice result
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
how much does sample handling on my end affect the number
which lab
i had a result i am fairly sure was a handling error on my side and i logged it as such
is a purity-only test worth the money if underfill is the common failure
i test roughly every tenth vial. it is a sampling strategy, not paranoia
a supplier disputing a result is rare here and it has never gone well for the supplier
lot-log.csv
118 rows · not retained in the public archive
thats within range
a point or two between the certificate and an independent result is inside what two labs disagree by
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quick one my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
posting my Janoshik result on lot C-4402, what do people make of it
nice result
certificate said 99.4 and the independent came back 98.1, is that a problem
bea_reconstitutesa supplier disputing a result is rare here and it has never gone well for the supplier
weigh the vial before you reconstitute. it costs nothing and catches the common failure
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
a result without a lot number and a purchase date is an anecdote with a pdf attached
my sheet has 4 lots from WXT with a spread under a point, which is tight
unrelated but i told JEEP about a result they would not have liked and they did not argue. credit where it is due
my vial assayed under label but the purity was fine, which matters more
log the boring results too. a channel that only records failures produces a false picture, n of 1 obviously
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind, thats one data point
selection bias
Channel stats, last 30 days: 116 messages from 17 members.
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coming back after 2 months with a follow up result, where do i put it
do the results in this channel skew because people test when suspicious
whats the lot
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thats a fill problem
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
one data point
update from 26 months ago: retested the same supplier, result came back better, logged both
if the vial has been through a bad transit you are testing the transit as much as the supplier
log the lot number
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
underfill is more common than impurity. if you only test purity you are testing the less likely failure
how do you separate batch variance from supplier variance