vialroom

#test-results 2025-12-17

Wednesday38 messages8 participantstimes are UTC
Highlights from this day
  • lisbon_lot — does anyone log the negative results, the boring ones 20:29
  • assay_not_purity — anyone had a result they think was a lab error rather than a bad vial underfill is more common than impurity. if you only test purity you are testing the less likely… 20:35
  • assay_not_purity — whats the worst result anyone has logged and what happened next a result without a lot number and a purchase date is an anecdote with a pdf attached 20:49
  • lyophile_liv — right so if you are testing to settle an argument you will not settle it with n of 1 22:09
  • net_peptide — whats the underfill rate people are actually seeing 22:14
AN

sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm

the honest limits: hobby chain of custody is weak and any result here should be read with that in mind

underfill is more common than impurity. if you only test purity you are testing the less likely failure, thats one data point

update from 9 months ago: retested the same supplier, result came back better, logged both, happy to be corrected

certificate said 98.6 and the independent came back 99.4, is that a problem

test it again

AN

anyone had a result they think was a lab error rather than a bad vial
underfill is more common than impurity. if you only test purity you are testing the less likely failure

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AN

whats the worst result anyone has logged and what happened next
a result without a lot number and a purchase date is an anecdote with a pdf attached

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LL

how do you post a result so it is actually useful to somebody in a year

my vial assayed under label but the purity was fine, which matters more

RS

99.2 against a certificate of 96.8 is fine. the same supplier landing low four times in a row is a question

LL

right so do the results in this channel skew because people test when suspicious

log the boring results too. a channel that only records failures produces a false picture

log the lot number

attach the pdf

unrelated but i have never regretted spending the money on a test. i have regretted not testing twice

TT

is it worth testing if the vial has already been through a warm transit

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NP

how many lots do you need before you can say anything about a supplier

NP

a single sample tells you about a single vial. that is genuinely all it tells you

LL

one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally

LL

right so if you are testing to settle an argument you will not settle it with n of 1

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NP

weigh the vial before you reconstitute. it costs nothing and catches the common failure

what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern, n of 1 obviously

whats the underfill rate people are actually seeing

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the widest spread in my data is about 2.6 percentage points across five lots from one supplier
i had a result i am fairly sure was a handling error on my side and i logged it as such

LL

a supplier disputing a result is rare here and it has never gone well for the supplier, ill dig out the number

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LL

sorry to jump in assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, thats one data point

LL

sorry to jump in the results in this channel skew because people test when they are suspicious. that is selection bias and it is real, i think