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c/hplc·submitted 1 year ago by u/marisol_frisk

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

Labbranch of 6 comments

three years of gradient threads, summarised so you do not have to read them, which sounds obvious until you try to state the evidence for it. Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely. Gave the…

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6 comments, started 1 year ago
u/cormac_roos177 points·1 year 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/rosa_sandvik63 points·1 year ago

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

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u/marisol_friskOP38 points·1 year ago

Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.

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u/marisol_friskOP118 points·1 year ago·edited

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

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u/kofi_ferreira148 points·1 year ago

Mass spectrometry answers identity.

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

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u/isabela_nilsen112 points·1 year ago

area percent is relative to what the detector saw and nothing else

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