April 28, 2010

It's in California.

One of my favorite acronyms was coined by Prof. Daniel P. Weitekamp of CalTech.

The sensitivity of nuclear magnetic resonance (NMR) is limited by the magnetic polarization (or alignment) of atomic nuclei, which is very small even in the strong magnets used for NMR – around one part in a million. If this could be increased, then the NMR signal would increase proportionally. So, there is room for many orders of magnitude enhancement in NMR signals.

Parahydrogen is a "spin isomer" of molecular hydrogen; it's just good old H2, but with the proton magnetizations pointed in opposite directions. What C.R. Bowers & D.P. Weitekamp showed in 1984 is that when you chemically add parahydrogen across a carbon-carbon double-bond in a molecule, then those newly-tacked-on protons arrive with close to full (100%) nuclear polarization, such that their NMR signals are almost a million times bigger than the signals from the other protons in the molecule. Cool!

What did the inventors dub this new method? Why, they called it "Parahydrogen And Synthesis Allow Dramatically Enhanced Nuclear Alignment", or PASADENA.

Did I mention that they're at the California Institute of Technology, which is in the state of California, in the city of Pasadena?

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