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c/hplc·submitted 5 months ago by u/hydration_hank

three years of HPLC threads, summarised so you do not have to read them

Questionbranch of 10 comments

three years of HPLC threads, summarised so you do not have to read them. Making the case below, and I expect to lose some of it in the comments. UV response is not uniform across species. At 214nm you are looking at the peptide bond, which is why it is the working wavelength for this class; at 280nm you only see…

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10 comments, started 5 months ago
u/teodor_szabo29 points·5 months 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/rasmus_kimani20 points·5 months ago

ghost peak, check the plumbing first, it is always the plumbing

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u/adaeze_batista5 points·5 months ago

Yes — system suitability first. Without it the number is an assertion about the instrument, not the sample.

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u/fatima_yildiz6 points·5 months ago·edited

Yes — system suitability first.

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

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u/endotoxin_elliemicro8 points·5 months ago

Mass spectrometry answers identity.

Adding one practical thing — run the blank. It answers this before anyone has to argue about it.

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u/andres_restrepo5 points·5 months ago

Same view — reporting the gradient is what makes a result checkable rather than merely stated.

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u/saskia_bakker7 points·5 months ago

Same view — reporting the gradient is what makes a result checkable rather than merely stated.

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

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u/honest_syringe_pls2 points·5 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/dizzy_on_standing1 point·5 months ago

How old is the column and roughly how many injections has it seen?

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u/hydration_hankOP21 points·5 months ago·edited

Mass spectrometry answers identity.

This is the whole methodological point of the board in one line.

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