whats the underfill rate people are actually seeing
#test-results 2025-01-24
Friday43 messages7 participantstimes are UTC
Highlights from this day
- LC_MS_Lena — what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern 20:49
- assay_not_purity — how do you post a result so it is actually useful to somebody in a year 20:59
- assay_not_purity — i test roughly every tenth vial. it is a sampling strategy, not paranoia 21:05
log the lot number
lot-log.csv
315 rows · not retained in the public archive
one data point
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind, happy to be corrected
my vial assayed under label but the purity was fine, which matters more
a result without a lot number and a purchase date is an anecdote with a pdf attached
i have never regretted spending the money on a test. i have regretted not testing twice
log the boring ones
log the boring results too. a channel that only records failures produces a false picture
follow up my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ, from memory
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quick one assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, i could be wrong
peptidemeter-summary-g-0641.pdf
2 pages · 164 KB · not retained in the public archive
how do you separate batch variance from supplier variance
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
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
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how many lots do you need before you can say anything about a supplier
if you are testing to settle an argument you will not settle it with n of 1
quantity testing is usually a separate line item and it is the one worth paying for
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
sorry to jump in a supplier disputing a result is rare here and it has never gone well for the supplier, we shall see
if the vial has been through a bad transit you are testing the transit as much as the supplier
how do you post a result so it is actually useful to somebody in a year
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post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later, your mileage will differ
i test roughly every tenth vial. it is a sampling strategy, not paranoia
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sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
a single sample tells you about a single vial. that is genuinely all it tells you
thats a fill problem
update from 3 months ago: retested the same supplier, result came back better, logged both
coming back after 4 months with a follow up result, where do i put it
i told KP about a result they would not have liked and they did not argue. credit where it is due, happy to be corrected
does a bad result on one lot condemn the whole supplier
is a purity-only test worth the money if underfill is the common failure
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a point or two between the certificate and an independent result is inside what two labs disagree by
test it again
my sheet has 5 lots from KP with a spread under a point, which is tight
sorry to jump in has a supplier ever disputed a result posted here
is quantity testing available as a separate thing or bundled
follow up 97.4 against a certificate of 99.4 is fine. the same supplier landing low four times in a row is a question
weigh the vial before you reconstitute. it costs nothing and catches the common failure
is anyone tracking results over time in a way they would share
coming back to this thats within range
quantity testing is usually a separate line item and it is the one worth paying for
anyone tested the same lot twice at different labs
weigh it first
Digest for the week of 2024-10-13 has been published.
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