one data point
#test-results 2024-11-13
Wednesday32 messages8 participantstimes are UTC
Highlights from this day
- area_percent — i told ERP about a result they would not have liked and they did not argue. credit where it is due 10:55
- ms_ms_mira — has a supplier ever disputed a result posted here 10:58
- LC_MS_Lena — certificate said 98.6 and the independent came back 99.4, is that a problem 12:55
- assay_not_purity — if the vial has been through a bad transit you are testing the transit as much as the supplier 13:28
Reminder set. I will post here in 5 days.
a single sample tells you about a single vial. that is genuinely all it tells you
i told ERP about a result they would not have liked and they did not argue. credit where it is due
🔥3
weigh the vial before you reconstitute. it costs nothing and catches the common failure
has a supplier ever disputed a result posted here
👀8
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
one bad test does not condemn a supplier. one good test does not clear one. both halves get ignored equally, someone check my working
underfill is more common than impurity. if you only test purity you are testing the less likely failure
[edited]my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
whats the lot
is a purity-only test worth the money if underfill is the common failure
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
coming back after 19 months with a follow up result, where do i put it
whats the underfill rate people are actually seeing
if you are testing to settle an argument you will not settle it with n of 1
thats not great
💀17
96.8 against a certificate of 97.4 is fine. the same supplier landing low four times in a row is a question
whats the worst result anyone has logged and what happened next
genuine question does a bad result on one lot condemn the whole supplier
quantity testing is usually a separate line item and it is the one worth paying for
certificate said 98.6 and the independent came back 99.4, is that a problem
📈6🤝5
update on the earlier thing update from 20 months ago: retested the same supplier, result came back better, logged both
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern, ymmv
[edited]if the vial has been through a bad transit you are testing the transit as much as the supplier
❤️1👍1🧊13
my vial assayed under label but the purity was fine, which matters more
my sheet has 9 lots from QST with a spread under a point, which is tight
how do you separate batch variance from supplier variance
Inter-lab diff for lot H-2814: 99% vs 99.4%. Within expected range.