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c/hplc·submitted 3 months ago by u/rania_okonkwo

[Meta] the LC-MS rule is doing its job and people should stop complaining

Labbranch of 10 comments

the LC-MS rule is doing its job and people should stop complaining — posting the reasoning in public because a policy you cannot inspect is just a preference. The system suitability argument, since it comes up whenever somebody posts a number without one. Before the sample result means anything, the instrument has to…

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10 comments, started 3 months ago
u/georgi_chowdhury68 points·3 months ago

two labs, two gradients, two honest answers

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u/honest_syringe_202553 points·3 months ago

What wavelength, and what was the gradient?

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u/rania_okonkwo13 points·3 months ago

you cannot report to two decimals off that baseline

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u/rania_okonkwoOP6 points·3 months ago

Sent the same vial to PeptideMeter and VendorInvestigate. 99.6% against a claimed 99.0%. The difference was the gradient, not the material.

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u/matias_salgado4 points·3 months ago

Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.

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u/vikram_asante4 points·3 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/ewan_marchand2 points·3 months ago

Is that baseline drawn by the software or by hand?

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u/hugo_bergstrom11 points·3 months ago

Chased a ghost peak for three weeks. It was the plumbing. It is always the plumbing.

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u/runa_cabrera45 points·3 months ago

What did system suitability look like on that sequence?

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u/quiet_reader_9910 points·3 months ago

Gave the same trace to two people I trust and got two integrations about a point apart. That was the most educational afternoon I have had here.

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