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c/hplc·submitted 2 years ago by u/hana_lehtinen

chromatogram is the most under-discussed thing on this board

Correctionbranch of 7 comments

chromatogram is the most under-discussed thing on this board. I have gone back and forth on this for months. 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. Area…

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7 comments, started 2 years ago
u/marisol_frisk309 points·2 years ago

Mass spectrometry answers identity. UV purity answers relative quantity under the run conditions. A document with one and not the other is answering half the question, and the half it answers should be stated.

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u/mass_spec_maggieMOD247 points·2 years ago

Method questions stay here; supplier claims go to c/vendorvetting with a document attached.

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u/hana_lehtinenOP132 points·2 years ago

Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.

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u/niels_lindqvist-5 points·2 years ago

What wavelength, and what was the gradient?

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u/sofia_petrescu89 points·2 years ago

I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.

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u/step_count_stan32 points·2 years ago

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

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u/reverse_image_ron60 points·2 years 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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