97.4 against a certificate of 98.1 is fine. the same supplier landing low four times in a row is a question, someone check my working
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#test-results 2025-10-13
Monday48 messages10 participantstimes are UTC
Highlights from this day
- ring_size_down — 97.4 against a certificate of 98.1 is fine. the same supplier landing low four times in a row is a question, someone check my working 14:50
- halifax_hplc — a point or two between the certificate and an independent result is inside what two labs disagree by 15:39
- private_script_pri — my sheet has 4 lots from Homopeptide with a spread under a point, which is tight 17:42
sorry to jump in sample handling on your end absolutely affects it. draw cleanly, ship fast, do not let it sit warm
my read after three years of this: purity is mostly fine across the market and fill consistency is where suppliers differ
do you test every order or sample it
thats not great
one data point
selection bias
update from 9 months ago: retested the same supplier, result came back better, logged both
thats a fill problem
a point or two between the certificate and an independent result is inside what two labs disagree by
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while im here if the vial has been through a bad transit you are testing the transit as much as the supplier
is quantity testing available as a separate thing or bundled
assay under label with good purity means you got less of the right thing. that is a fill problem, not a synthesis problem
whats the underfill rate people are actually seeing
ok so a supplier disputing a result is rare here and it has never gone well for the supplier, i have it written down somewhere
the results in this channel skew because people test when they are suspicious. that is selection bias and it is real, someone check my working
[edited]a single sample tells you about a single vial. that is genuinely all it tells you
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weigh it first
when did you buy it
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how much does sample handling on my end affect the number
*PeptideMeter not the other one
the widest spread in my data is about 2.6 percentage points across five lots from one supplier
is anyone tracking results over time in a way they would share
quantity testing is usually a separate line item and it is the one worth paying for
the honest limits: hobby chain of custody is weak and any result here should be read with that in mind
a point or two between the certificate and an independent result is inside what two labs disagree by
does anyone log the negative results, the boring ones
i had a result i am fairly sure was a handling error on my side and i logged it as such
i told KP about a result they would not have liked and they did not argue. credit where it is due
thats within range
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posting my Janoshik result on lot A-2601, what do people make of it
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log the boring ones
log the boring results too. a channel that only records failures produces a false picture
attach the pdf
*Medutest not the other one
my sheet has 4 lots from Homopeptide with a spread under a point, which is tight
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how many lots do you need before you can say anything about a supplier
17:49tenpence pinned a message to this channel
is it worth testing if the vial has already been through a warm transit
whats the worst result anyone has logged and what happened next
i have never regretted spending the money on a test. i have regretted not testing twice, ask me again in a month
certificate said 99.4 and the independent came back 98.6, is that a problem
my result contradicts the supplier certificate, do i tell them
post the lot, the purchase month, the lab, the number, and what you were expecting. that makes it useful later
what interests me is when the gap goes the same direction every time. once is noise, three times is a pattern
[edited]Purity check: no report on file for lot A-2601. Nothing logged either way.
underfill is more common than impurity. if you only test purity you are testing the less likely failure
do the results in this channel skew because people test when suspicious