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c/hplc·submitted 4 months ago by u/blunt_coldbox_2024

[Meta] proposal — a flair for integration posts

Questionbranch of 9 comments

proposal — a flair for integration posts. Comments open, and the wording is genuinely up for discussion. 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 tryptophan, tyrosine and phenylalanine.…

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9 comments, started 4 months ago
u/rina_bergstrom268 points·4 months ago

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.

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u/mateusz_mensah115 points·4 months ago

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that d

Agreed. And the corollary is that the method line on a certificate is not decoration, it is the number’s provenance.

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u/honest_syringe_202568 points·4 months ago

two labs, two gradients, two honest answers

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u/mateusz_mensah-19 points·4 months ago

Same method at both labs, or two different gradients?

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u/blunt_coldbox_2024OP76 points·4 months ago

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

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[deleted]390 points·4 months ago

[deleted]

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u/canada_coverage208 points·4 months ago

Correction: that is a tailing factor, not a plate count. Different diagnostics for different problems.

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u/honest_syringe_pls302 points·4 months ago

axis labels or the trace is decoration

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u/blunt_coldbox_2024OP223 points·4 months ago

axis labels or the trace is decoration

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

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