the HPLC thing finally clicked for me and I want to write it down
The title is the argument: the HPLC thing finally clicked for me and I want to write it down. Here is the rest of it.
JEEP sent me the column, the gradient and the theoretical mass without being asked. That is a short list and they are on it.
Retention time shifted 0.4 minutes and I assumed the worst. It was the column temperature.
Gave the same trace to two people I trust and got two integrations about a point apart. That was the most educational afternoon I have had here.
If two or three other people have done the same thing we might actually learn something. Alone it is an anecdote.
best — the order this archive was captured in
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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a blank injection between samples costs four minutes and settles most arguments
Method questions stay here; supplier claims go to c/vendorvetting with a document attached.
That figure cannot be quoted to two decimals off that baseline. The precision is not in the data.
Method questions stay here; supplier claims go to c/vendorvetting with a document attached.
peak_area_pete is right — the integration choice is a decision and it should be stated alongside the result.
Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.
Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.
two labs, two gradients, two honest answers
Yes — system suitability first. Without it the number is an assertion about the instrument, not the sample.
Can you post the trace with the axes labelled?
- 1Method questions stay here; supplier claims go to c/vendorvetting with a…8 comments in this branch · started by u/peak_area_pete