LC-MS — what am I missing here — that is what I am asking, and I have already read the wiki twice. Bought a second-hand instrument and learned more in six months of…
u/week_four_wall
Everyone quits at week four. Do not quit at week four.
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Overview — page 3 of 3
comment on [Question] LC-MS — what am I missing here in c/hplc · 1 points · 9 months ago
Is that baseline drawn by the software or by hand?
comment on [Question] LC-MS — what am I missing here in c/hplc · 6 points · 9 months ago
Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.
comment on [Question] LC-MS — what am I missing here in c/hplc · 1 points · 9 months ago
What wavelength, and what was the gradient?
comment on [Question] how do you actually verify SURPASS in c/trialwatch · 2 points · 10 months ago
How long was the randomised phase before any extension?
comment on [Meta] proposal — a flair for LC-MS posts in c/hplc · 243 points · 10 months ago
Same method at both labs, or two different gradients?
comment on [Meta] proposal — a flair for LC-MS posts in c/hplc · 12 points · 10 months ago
Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.
comment on [Meta] proposal — a flair for LC-MS posts in c/hplc · 53 points · 11 months ago
Cosigning the wavelength point.
This is the whole methodological point of the board in one line.
proposal — a flair for LC-MS posts. Short post, long comment section, probably. QYB sent me the column, the gradient and the theoretical mass without being asked. That…
comment on [Question] integration — what am I missing here in c/hplc · 15 points · 1 year ago
I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.
comment on SURPASS — 17 things I got wrong before I got it right in c/trialwatch · 1 points · 1 year ago
Agreed on comparators. "Superior" means nothing until you know superior to what and at what dose.
comment on does chargeback actually matter or is it forum lore at this point in c/cryptopay · 38 points · 1 year ago
Confirmations are the count of blocks built on top of the one containing your transaction. Until there are some, the transaction is not settled in any meaningful sense.
comment on SURPASS — 11 things I got wrong before I got it right in c/trialwatch · 10 points · 1 year ago
Relative risk reduction without the baseline rate is uninterpretable. A large relative reduction on a small absolute risk is a small absolute benefit.
comment on how much of what we believe about gas fees actually comes from USDC threads in c/cryptopay · 23 points · 1 year ago
nobody legitimate needs the payment in the next ten minutes
comment on [Question] chromatogram — what am I missing here in c/hplc · 0 points · 1 year ago
Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.
comment on [Question] chromatogram — what am I missing here in c/hplc · 25 points · 1 year ago
That is area percent, not mass percent. The trace cannot give you the second one.
comment on jurisdiction — 3 things I got wrong before I got it right in c/customs · 19 points · 1 year ago
if it matters, ask somebody qualified in your own jurisdiction
Title says it — split one vial across PeptideMeter and VendorInvestigate — 96.8% and 99.1% — so here is the boring supporting detail that makes it worth anything. The…
comment on why does nobody talk about gradient in c/hplc · 25 points · 1 year ago
Same method at both labs, or two different gradients?
comment on why does nobody talk about SELECT in c/trialwatch · -13 points · 1 year ago
Which trial, and which arm?
comment on [Meta] the confirmations rule is doing its job and people should stop complaining in c/cryptopay · 32 points · 1 year ago
send a test amount first if the total is large
Adding the cheap insurance — test amount first on anything large.
comment on the crypto thing finally clicked for me and I want to write it down in c/cryptopay · -38 points · 1 year ago
Disagree — a quote expiry is normal when a rate is being held. Pressure to decide immediately is a different thing.
comment on [Discussion] TRIUMPH is doing more work than we give it credit for in c/trialwatch · 145 points · 1 year ago
A confidence interval is the range of effects compatible with the data. Two trials with overlapping intervals have not disagreed, whatever their point estimates look like next to each other.
comment on someone explain LC-MS to me like I have not read a paper in years in c/hplc · 1 points · 1 year ago
214nm sees the peptide bond, 280nm sees the aromatics
comment on method development — 10 things I got wrong before I got it right in c/hplc · 11 points · 1 year ago
report the method or do not report the number
comment on three years of compounding threads, summarised so you do not have to read them in c/glp1aus · 215 points · 1 year ago
Cosigning on asking the pharmacy to check the wholesaler. It converts speculation into a fact in one phone call.
comment on how much of what we believe about gradient actually comes from purity threads in c/hplc · 61 points · 1 year ago
reproducibility beats resolution if you only get one of them
comment on how much of what we believe about gradient actually comes from purity threads in c/hplc · 80 points · 1 year ago
Ran a blank after a high-concentration injection and found the carryover I had been calling an impurity.
comment on why does nobody talk about shortage in c/glp1aus · 1 points · 2 years ago
Push back: the compounded arrangements changed and the advice you are quoting predates the change.
comment on why does nobody talk about shortage in c/glp1aus · 31 points · 2 years ago
Same.
Disagreeing with this bit: that advice predates the change in compounded arrangements.
comment on help me understand method development, I have read the wiki twice in c/hplc · 45 points · 2 years ago
LC-MS for identity, UV for relative quantity
comment on SURPASS — 12 things I got wrong before I got it right in c/trialwatch · 79 points · 2 years ago
That is the 68-week readout, not the 72-week one. Different trial, different duration.
comment on [Lab] 16th independent test on ERP — 97.4% on a claimed 97.0%, and the trend is the interesting part in c/hplc · 228 points · 2 years ago
A shoulder that does not baseline-resolve cannot be quantified honestly. You can report it as an unresolved shoulder, which is useful information, or you can develop the method until it resolves.
comment on [Lab] KP cagri — VendorInvestigate came back 98.1% against a claimed 97.5% in c/hplc · 527 points · 2 years ago
214nm sees the peptide bond, 280nm sees the aromatics
Title says it — KP cagri — VendorInvestigate came back 98.1% against a claimed 97.5% — so here is the boring supporting detail that makes it worth anything. 98.1% and…
comment on [Question] is 94.2% actually fine or am I being sold a rounding error in c/hplc · 415 points · 2 years ago
Reading a trace posted here, in the order I actually look at things.
Axes first — if the wavelength and the time axis are not labelled, I stop. Then the baseline: where has it been drawn, and does the drawing absorb anything. Then peak shape: fronting, tailing, a shoulder that never resolves. Then the blank, if one was run, for carryover.
Only after all of that do I look at the percentage, and by then I usually know how much weight it deserves. The number is the last thing on the page and the first thing everybody argues about, which is exactly backwards.
comment on [Question] New Zealand — has anyone got a straight answer on chargeback in c/cryptopay · 11 points · 2 years ago
Was there a memo or tag requirement on that chain?
comment on [Question] New Zealand — has anyone got a straight answer on chargeback in c/cryptopay · 10 points · 2 years ago
Got a quote with a fifteen-minute expiry and assumed it was a pressure tactic. It was just a held rate.
comment on [Question] New Zealand — has anyone got a straight answer on chargeback in c/cryptopay · 96 points · 2 years ago
Asked which networks WWB accepted before ordering and picked the cheapest one at that hour. Saved more than the difference in price.
New Zealand — has anyone got a straight answer on chargeback, and I want the answer with the reasoning attached rather than just the conclusion. Some chains require a…