« More on Question Four |
Main
| Why Carbon Matters »
March 30, 2005
Lost Arts
Posted by Derek
(This is an update of a three-year-old posting - it seemed like a good time to bring it back.)
Since I was speaking about NMR, it's a good thing for chemists to remember that this tool wasn't always there for us. For those of you not in the field, I can say without exaggeration that we'd have to close up shop without it. It's so valuable that it's crowded out older, perfectly reasonable techniques like infrared spectroscopy.
Fellow chemists, raise your hands: Who's taken an IR spectrum in the last six months? OK, you folks who are characterizing compounds for your dissertations can put yours down. Anyone from Switzerland who's writing a paper for Helvetica Chimica Acta (where every new compound is characterized practically down to how it tastes) can put their hand down, too. Anyone left?
I didn't think so. It's a lost art. I haven't taken one since the late 1980s, myself. It's true that you can see all sorts of structural information in an IR, but why would you bother? NMR will tell you the same thing and plenty more at the same time, things you could stare an an infrared spectrum until your eyes cross and never be able to determine.
For an even more lost art, consider ultraviolet/visible spectroscopy. Go back to the 1940s and 50s and the journals are full of UV/Vis spectra, reproduced in all their near-featureless glory. I took a few of these as an undergraduate, and I don't recall ever doing any since. Inorganic chemists can be interested in these wavelengths, but darn few synthetic organic chemists are.
But don't get me wrong - I'm not asking to return to the days when those techniques meant something. Far from it. But every so often, when we're complaining that the NMR machine is taking an extra couple of minutes to automatically run our sample, it's worth taking a minute to think about the alternative.
Comments (4)
+ TrackBacks (0) | Category: Life in the Drug Labs
- RELATED ENTRIES
- › Shire's Replagal Problems: An Inside Look?
- › Bungled Structure, And How
- › Roche Closes Nutley, Once Its US R&D Home
- › The Next Five Years in the Drug Industry
- › A Kinase Inhibitor Learns Something New
- › The Good Ol' Friedel-Crafts
- › Merck's Madagascar Marketing Mess
- › Scientific Literacy: Where Do You Stop?
1. SP on March 31, 2005 11:20 AM writes...
Do you ever run an HPLC? I suppose you have a DAD or VWD detector on there? Which is, you know, measuring pieces of the (or the whole)UV/Vis spectrum?
Permalink to Comment2. Jason on March 31, 2005 12:20 PM writes...
Interpretation of IR spectra probably offer the clearest example of undergrads fitting conclusions to data rather than the other way around.
In my advanced organic lab, we were given unknowns to identify using IR, C13 and H1 NMR, DEPT, and MS. I remember having the compound fully identified using the other stuff before turning to the IR and deciding that it had peaks for whatever prominent features my compound possessed (yeah...that could reasonably be an amine peak right there...)
I just pray no one ever hands me an IR spec for benzene and tells me to identify it or lose my job. I'd be screwed.
Permalink to Comment3. Derek Lowe on March 31, 2005 2:23 PM writes...
Point taken about the UV detectors - up to a point. That illustrates how far UV spectroscopy has fallen from its days as a way to prove structure, though - now it's a part stuck on the side of another machine. In one sense, I use UV absorption every day. But I haven't run a full UV spectrum of a compound, in the hopes that it would tell me anything about it and its structure, in over twenty years.
Permalink to CommentFor NMR to fall into that state of disuse, we'd have to just be sticking compounds into the magnet to verify that they had hydrogens on them.
4. SP on March 31, 2005 2:41 PM writes...
Well, all of NMR won't fall to that point, but simple 1D proton might- everyone routinely runs all kinds of crazy pulse sequences, suppressions, NOEs, etc. What was the joke I once heard about acronyms and an NMR conference...
Permalink to CommentOn the biological side, supposedly traditional gels (agarose and acrylamide) are going out of favor in industry but are still the standard in academia.