DocX - 30-11-2023 at 13:00
So I just got offered a Varian UV-Vis spectrophotometer, Cary 3, just to pick up free of charge. I know nothing really about this machine, it's given
away with computer and keyboard but with a broken UV light.
Is this usable for me as a hobbyist? Can the UV light be replaced? Will I be able, with a reasonable learning curve and expense, to identify my
products (orgchem hobby tinkering) with this?
DraconicAcid - 30-11-2023 at 16:03
I've tried doing a bit of UV-Vis in organic, and found that the peaks are extremely broad, and not particularly informative.
I'd be very happy to have such a spec for transition metal coordination chemistry, though.
unionised - 1-12-2023 at 09:05
The big problem (in my experience) for organics with UV is that, unless it's connected to the end of a chromatograph, the impurities in your materials
may well absorb more strongly than the actual "sample".
(Just think about how often you see yellowish samples of materials that should be white).
On the other hand, it's a pretty good way of quantifying reasonably pure materials.
But it's really hard to argue with "free" as a price.
There's one pitfall. The deuterium lamps they often use are expensive.
You can get some way into the UV with a tungsten lamp, but D2 makes it a lot easier.
It's likely to be educational to try.
DocX - 1-12-2023 at 11:38
ok, thanks. I have zero experience in spectrophotometry, so this might be a too steep learning curve for me and a useless piece of machinery. But as
you say, "free" is a sweet deal. If it doesn't work for my purposes or skill, I'll just pass it along in the community in the same manner I got it
though 
.
Probably it'll be a while before I can get around to actually try it, but when I do I'll be likely to bombard this forum part with more detailed
questions.
phlogiston - 1-12-2023 at 16:00
Its not very well suited for identifying organic chemicals in general.
Its an excellent technique/instrument, however, for quantification of all kinds of analytes. Over the decades, there have been many methods developed
that will fairly specifically convert an analyte of interest into something that absorbs in the UV-VIS range. Its also very useful for enzymatic
assays.