log the lot number
#test-results 2025-05-19
Monday46 messages11 participantstimes are UTC
Highlights from this day
- VialBot — Inter-lab diff for lot D-0718: 99% vs 99.2%. Within expected range. 19:14
- VialBot — Purity check: no report on file for lot H-2814. Nothing logged either way. 19:41
- retention_time — update from 20 months ago: retested the same supplier, result came back better, logged both 20:08
- customs_owl — a single sample tells you about a single vial. that is genuinely all it tells you 20:19
- assay_not_purity — i had a result i am fairly sure was a handling error on my side and i logged it as such 21:17
Inter-lab diff for lot D-0718: 99% vs 99.2%. Within expected range.
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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
log the boring results too. a channel that only records failures produces a false picture
my result contradicts the supplier certificate, do i tell them
a single sample tells you about a single vial. that is genuinely all it tells you
nice result
Purity check: no report on file for lot H-2814. Nothing logged either way.
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what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
attach the pdf
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slightly off topic but assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem, happy to be corrected
[edited]my sheet has 4 lots from GL Biochem with a spread under a point, which is tight
whats the lot
a supplier disputing a result is rare here and it has never gone well for the supplier
update from 20 months ago: retested the same supplier, result came back better, logged both
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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
when did you buy it
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a single sample tells you about a single vial. that is genuinely all it tells you
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how much does sample handling on my end affect the number
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
thats a fill problem
test it again
one data point
thats within range
a point or two between the certificate and an independent result is inside what two labs disagree by
i had a result i am fairly sure was a handling error on my side and i logged it as such
i have never regretted spending the money on a test. i have regretted not testing twice
i had a result i am fairly sure was a handling error on my side and i logged it as such
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🤝4📈10⚠️5
if the vial has been through a bad transit you are testing the transit as much as the supplier
log the boring ones
selection bias
i test roughly every tenth vial. it is a sampling strategy, not paranoia
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update on the earlier thing the widest spread in my data is about 2.6 percentage points across five lots from one supplier
weigh the vial before you reconstitute. it costs nothing and catches the common failure, i have it written down somewhere
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a result without a lot number and a purchase date is an anecdote with a pdf attached, n of 1 obviously
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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does a bad result on one lot condemn the whole supplier
thats not great
right so if you are testing to settle an argument you will not settle it with n of 1
which lab
underfill is more common than impurity. if you only test purity you are testing the less likely failure
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally
update on the earlier thing i told KP about a result they would not have liked and they did not argue. credit where it is due
attach the pdf
has a supplier ever disputed a result posted here
99 against a certificate of 99.2 is fine. the same supplier landing low four times in a row is a question