how many lots do you need before you can say anything about a supplier
#test-results 2026-06-07
Sunday50 messages10 participantstimes are UTC
Highlights from this day
- flint_fills — coming back after 18 months with a follow up result, where do i put it 17:05
- flint_fills — i told JEEP about a result they would not have liked and they did not argue. credit where it is due 17:06
- adelaide_assay — 99.2 against a certificate of 98.1 is fine. the same supplier landing low four times in a row is a question, for what its worth 18:19
- adelaide_assay — my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ 19:29
- VialBot — Reminder set. I will post here in 5 days. 21:05
coming back after 18 months with a follow up result, where do i put it
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i told JEEP about a result they would not have liked and they did not argue. credit where it is due
thats not great
is a purity-only test worth the money if underfill is the common failure
if you are testing to settle an argument you will not settle it with n of 1, still working it out
nice result
selection bias
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, still working it out
[edited]attach the pdf
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anyone tested the same lot twice at different labs
is it worth testing if the vial has already been through a warm transit
a result without a lot number and a purchase date is an anecdote with a pdf attached
i had a result i am fairly sure was a handling error on my side and i logged it as such
a single sample tells you about a single vial. that is genuinely all it tells you, i have it written down somewhere
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
underfill is more common than impurity. if you only test purity you are testing the less likely failure
anyone had a result they think was a lab error rather than a bad vial
99.2 against a certificate of 98.1 is fine. the same supplier landing low four times in a row is a question, for what its worth
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when did you buy it
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
i have never regretted spending the money on a test. i have regretted not testing twice
*PeptideMeter not the other one
my vial assayed under label but the purity was fine, which matters more
update from 11 months ago: retested the same supplier, result came back better, logged both, not advice obviously
how do you separate batch variance from supplier variance
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
log the lot number
quantity testing is usually a separate line item and it is the one worth paying for
a supplier disputing a result is rare here and it has never gone well for the supplier, thats just me
log the boring results too. a channel that only records failures produces a false picture, from memory
thats a fill problem
test it again
log the boring ones
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
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the results in this channel skew because people test when they are suspicious. that is selection bias and it is real
my sheet has 4 lots from GL Biochem with a spread under a point, which is tight
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
does anyone log the negative results, the boring ones
a point or two between the certificate and an independent result is inside what two labs disagree by
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one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
i test roughly every tenth vial. it is a sampling strategy, not paranoia, i have it written down somewhere
if the vial has been through a bad transit you are testing the transit as much as the supplier, thats one data point
is anyone tracking results over time in a way they would share
Reminder set. I will post here in 5 days.
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which lab
sorry to jump in do you test every order or sample it
thats within range
whats the worst result anyone has logged and what happened next
does a bad result on one lot condemn the whole supplier
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