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c/coa·submitted 1 year ago by u/wrong_network_w

why does nobody talk about water content

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why does nobody talk about water content. Searched first, found three threads that contradict each other, hence the post. Asked for the storage condition behind the stability statement. Got it in a sentence. It is a two-line email and almost nobody sends it. The document I was worried about turned out to be a…

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6 comments, started 1 year ago
u/emeka_chowdhury1.5k points·1 year ago

UV at 214nm sees the peptide bond and picks up almost everything; at 280nm you are looking at aromatics only. Which wavelength the number came from is part of the number.

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u/laila_wojcik0 points·1 year ago

The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own.

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u/vito_chowdhury1 point·1 year ago

ask for the storage condition the stability statement was written against

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u/low_appetite_lisa1 point·1 year ago

Small fix — 214nm, not 280nm. It matters here because the impurity you are asking about barely absorbs at the longer wavelength.

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u/rohan_steiner1.2k points·1 year ago

UV at 214nm sees the peptide bond and picks up almost everything; at 280nm you are looking at aromatics only.

emeka_chowdhury has the distinction right — one is a fraction of the detector signal, the other is a fraction of the mass.

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u/andres_restrepo-29 points·1 year ago

What does the method line actually say? Not the technique — the column and the gradient.

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