my vial assayed under label but the purity was fine, which matters more
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#test-results 2026-01-16
Friday46 messages10 participantstimes are UTC
Highlights from this day
- LC_MS_Lena — the results in this channel skew because people test when they are suspicious. that is selection bias and it is real 12:44
- reed_reta — post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later, i have it written down somewhere 13:18
- never_for_sale — coming back to this a supplier disputing a result is rare here and it has never gone well for the supplier 14:16
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally, ill dig out the number
selection bias
whats the worst result anyone has logged and what happened next
anyone had a result they think was a lab error rather than a bad vial
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
posting my VendorInvestigate result on lot B-0114, what do people make of it
i told JEEP about a result they would not have liked and they did not argue. credit where it is due
weigh it first
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when did you buy it
does anyone log the negative results, the boring ones
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
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test it again
how do you separate batch variance from supplier variance
which lab
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i test roughly every tenth vial. it is a sampling strategy, not paranoia
genuine question update from 8 months ago: retested the same supplier, result came back better, logged both
weigh the vial before you reconstitute. it costs nothing and catches the common failure
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do the results in this channel skew because people test when suspicious
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later, i have it written down somewhere
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 / 10mgthats within range
i have never regretted spending the money on a test. i have regretted not testing twice
nice result
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coming back to this a point or two between the certificate and an independent result is inside what two labs disagree by
97.4 against a certificate of 99 is fine. the same supplier landing low four times in a row is a question
log the boring results too. a channel that only records failures produces a false picture
quantity testing is usually a separate line item and it is the one worth paying for
coming back to this a supplier disputing a result is rare here and it has never gone well for the supplier
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 / 10mgsorry to jump in sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
coa-f-1330.pdf
1 page · 643 KB · not retained in the public archive
genuine question is quantity testing available as a separate thing or bundled
if the vial has been through a bad transit you are testing the transit as much as the supplier
attach the pdf
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
ok so i had a result i am fairly sure was a handling error on my side and i logged it as such
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
thats not great
quick one coming back after 4 months with a follow up result, where do i put it
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
coming back to this a result without a lot number and a purchase date is an anecdote with a pdf attached
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how many lots do you need before you can say anything about a supplier
log the boring ones, i think
log the lot number
how much does sample handling on my end affect the number
certificate said 97.4 and the independent came back 98.6, is that a problem
which lab
if you are testing to settle an argument you will not settle it with n of 1
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