my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
#test-results 2025-11-20
Thursday49 messages11 participantstimes are UTC
Highlights from this day
- month_six_me — how much does sample handling on my end affect the number 21:05
- area_percent — unrelated but a result without a lot number and a purchase date is an anecdote with a pdf attached, your mileage will differ 22:14
- area_percent — the results in this channel skew because people test when they are suspicious. that is selection bias and it is real 23:09
posting my Janoshik result on lot KP-0925, what do people make of it
is a purity-only test worth the money if underfill is the common failure
how much does sample handling on my end affect the number
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 / 10mg✅16🔥12
*PeptideMeter not the other one
update from 2 months ago: retested the same supplier, result came back better, logged both
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does anyone log the negative results, the boring ones
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 / 10mgwhats the lot
thats not great
thats a fill problem
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
anyone had a result they think was a lab error rather than a bad vial
Batch lookup SG-1177: 4 independent reports on file, earliest 2025-10-09.
is it worth testing if the vial has already been through a warm transit
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
certificate said 99.2 and the independent came back 96.8, is that a problem
which lab
quantity testing is usually a separate line item and it is the one worth paying for, your mileage will differ
98.1 against a certificate of 99 is fine. the same supplier landing low four times in a row is a question
*Janoshik not the other one
a single sample tells you about a single vial. that is genuinely all it tells you
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my vial assayed under label but the purity was fine, which matters more
how many lots do you need before you can say anything about a supplier
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
genuine question has a supplier ever disputed a result posted here
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the widest spread in my data is about 2.6 percentage points across five lots from one supplier, take that with a pinch of salt
my sheet has 9 lots from QSC with a spread under a point, which is tight
unrelated but a result without a lot number and a purchase date is an anecdote with a pdf attached, your mileage will differ
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thats within range
whats the worst result anyone has logged and what happened next
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if the vial has been through a bad transit you are testing the transit as much as the supplier, take that with a pinch of salt
log the boring results too. a channel that only records failures produces a false picture, i have it written down somewhere
does a bad result on one lot condemn the whole supplier
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nice result
sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
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a supplier disputing a result is rare here and it has never gone well for the supplier
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
how do you post a result so it is actually useful to somebody in a year
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
one data point
i had a result i am fairly sure was a handling error on my side and i logged it as such, thats just me
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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*Medutest not the other one
a point or two between the certificate and an independent result is inside what two labs disagree by
do you test every order or sample it
whats the underfill rate people are actually seeing
my sheet has 8 lots from SWB with a spread under a point, which is tight
when did you buy it