bought a second-hand HPLC. worst best decision of my life. AMA
Two years ago I bought a decommissioned system for less than a decent bicycle. Since then I have learned more analytical chemistry than I ever wanted and spent more evenings on plumbing than on chemistry.
What it changed: I stopped arguing about purity numbers and started producing them. I also stopped trusting my own numbers, which is a strange result and I think the correct one.
Ask me anything. The honest answer to most questions is "it was the seals".
best — the order this archive was captured in
method development is 90% mobile phase and 10% crying. which percentage were the two years
year one was 90% crying. year two is closer to your ratio.
the crying is the plumbing. it is always the plumbing. every ghost peak i have ever chased was a fitting.
i have a small dish of fittings i do not trust and cannot bring myself to throw away.
every lab has this dish. every single one.
genuine question — did it change what you buy, or just how you talk about it?
Both, but not in the direction I expected.
I buy from fewer places and I test more of what I buy. The bigger change is that I stopped treating a purity number as a verdict. Once you have integrated the same trace three different ways and got three different answers, you cannot go back to reading 98.6 as a fact about the world.
Which sounds like nihilism and is not. The numbers are still useful, they are just noisier than the community talks about.
this is the most epistemically healthy comment on this site this month
next purchase should be a used single-quad if you can find one. identity is the question UV cannot answer and you are one instrument away from answering it.
do not tempt me. edit: i have already looked. twice.
For anyone reading this and getting ideas: the useful part is not the instrument, it is that they post the raw trace. You can contribute to this community at zero cost by paying a service and posting the report.
"worst best decision" is doing so much work in that title
- 1method development is 90% mobile phase and 10% crying. which percentage were…6 comments in this branch · started by u/gradient_goblin