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Single comment threadYou are looking at one branch of [Lab] split one vial across VendorInvestigate and PeptideMeter — 94.2% and 93.7% — 33 comments in the full submission. View in context.
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c/hplc·submitted 1 months ago by u/micro_bump_mick

[Lab] split one vial across VendorInvestigate and PeptideMeter — 94.2% and 93.7%

Labbranch of 10 comments

Right: split one vial across VendorInvestigate and PeptideMeter — 94.2% and 93.7%. I paid for this one myself, nobody sent me anything, and the receipts are in the comments. The numbers the title promised, since a headline without them is worthless: 94.2% and 93.7%. Everything below is context for those. Retention…

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10 comments, started 1 months ago
u/saskia_bakker105 points·1 months ago

Careful — you are treating retention time as identity. Two things can co-elute and the trace will not tell you.

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u/andres_restrepo25 points·1 months ago

Ran a blank after a high-concentration injection and found the carryover I had been calling an impurity.

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u/gustav_solberg-27 points·1 months ago·edited

WXT sent me the column, the gradient and the theoretical mass without being asked. That is a short list and they are on it.

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u/clara_danquah1 point·1 months ago

integration decisions move the number more than the sample does

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u/chain_confirm_cpayments50 points·1 months ago

Push back: a longer run is not automatically better resolution. You are trading peak width for time and the ratio is what matters.

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u/liv_okafor26 points·1 months ago

That is area percent, not mass percent. The trace cannot give you the second one.

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u/two_mil_or_one16 points·1 months ago

That is area percent, not mass percent.

Disagreeing with this bit: that spread is ordinary inter-lab variance, not a disagreement about the material.

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u/gustav_solberg18 points·1 months ago

Yes. Retention time is a hypothesis about identity. Mass is the answer.

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u/chain_confirm_cpayments31 points·1 months ago·edited

Correction: that is a tailing factor, not a plate count. Different diagnostics for different problems.

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u/honest_syringe_202524 points·1 months ago

you cannot report to two decimals off that baseline

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