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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 6 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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6 comments, started 3 months ago
u/zeynep_zielinski255 points·3 months ago

Can you post the trace with the axes labelled?

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u/sig_figs_sammod · analytical154 points·3 months ago

Can you post the trace with the axes labelled?

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

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u/two_mil_or_one323 points·3 months ago

Do you have the mass, or only the UV trace?

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u/fatima_yildiz363 points·3 months ago

LC-MS for identity, UV for relative quantity

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u/crosspost_bot_no230 points·3 months ago

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the purity figure is unanchored.

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u/marit_mensa290 points·3 months ago

Disagree. Inter-lab spread of a point or two on this assay is ordinary and calling it a discrepancy misleads people.

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