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

[Lab] split one vial across Janoshik and Medutest — 98.7% and 98.3%

Labbranch of 8 comments

Short version of the title, which is already short: split one vial across Janoshik and Medutest — 98.7% and 98.3%. Longer version underneath. Since the title puts numbers in the shop window: 98.7% and 98.3%. Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading…

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8 comments, started 1 year ago
u/rina_nascimento48 points·1 year ago

Agreed, and it is why QYB printing the column and gradient on the certificate is genuinely useful rather than decorative.

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u/zeynep_zielinski17 points·1 year ago

axis labels or the trace is decoration

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u/alcohol_aversion14 points·1 year ago

Careful — you are treating retention time as identity. Two things can co-elute and the trace will not tell you.

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u/cormac_roos9 points·1 year ago·edited

Careful — you are treating retention time as identity.

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

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u/mateusz_mensah11 points·1 year ago

a blank injection between samples costs four minutes and settles most arguments

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u/saskia_bakker14 points·1 year ago

That is area percent, not mass percent. The trace cannot give you the second one.

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u/cagrilintide_enthusiast9 points·1 year ago

Right. And a blank between injections settles the carryover argument before it starts.

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