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c/hplc·posted 7 months ago by u/insulin_syringe_ian

[Discussion] we are measuring LC-MS at the wrong time and calling it noise

Discussion Cold Box ×5 Slow Clap ×1 Clean Column ×1

The title is the argument: we are measuring LC-MS at the wrong time and calling it noise. Here is the rest of it.

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

Retention time shifted 0.4 minutes and I assumed the worst. It was the column temperature.

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.

That is everything I have. The rest is opinion and I have tried to keep it out.

11,753 up / 8,769 down57% upvoted29 commentsid zt1e4n9 Dec 2025

29 comments

5 in this archive, depth 2

best — the order this archive was captured in

u/cagrilintide_enthusiast248 points·7 months ago

Resolution between two peaks depends on retention, selectivity and efficiency. A shallower gradient buys retention and usually resolution, at the cost of peak width and run time.

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u/lina_novak172 points·7 months ago

Cosigning the wavelength point. Half the disagreements in this board are two people looking at different detectors.

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u/yara_boateng71 points·7 months ago

Resolution between two peaks depends on retention, selectivity and efficiency.

cagrilintide_enthusiast is right — the integration choice is a decision and it should be stated alongside the result.

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u/hplc_hobbyistMOD165 points·7 months ago

Retitled: the original claimed a comparison the post does not actually make.

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u/hedda_ekstrom138 points·7 months ago

Not convinced by that integration. Dropping the baseline there absorbs part of the shoulder into the main peak.

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