Liquid Helium, NMR and Chemistry

1. Liquid Helium is a very useful material. It is the coldest substance on Earth (~5 Kelvin).

2. One of its uses is to cool superconducting cryomagnets.

3. Cryomagnets are used in Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI)

4. NMR is widely used in qualitative analysis. You can think of it as the chemist's "eye". Using NMR, we can "see" things, without it, we work in the dark.

5. For example, would you know the difference between regular sugar (sucrose), glucose, fructose and aspartame (an artificial sweetener)? If you were to use all five of your senses, would you know the difference?

6. This problem is quite easy if one knows NMR. Of course, chemists use NMR to tackle tougher problems, e.g. to solve the identity of a newly discovered, previously unknown formula of an experimental cancer drug.

7. Without NMR, life is very difficult for the chemist. Without liquid Helium, NMR is useless.

8. A friend once told me a story that the government of Pakistan was given an NMR machine for free in the 1980s. It was the country's first NMR instrument, and previously their chemists had to work in the "dark".

9. However, the NMR sat idly and was not used. The Pakistanis didn't have liquid Helium.

10. Most of us are familiar with Helium GAS, which is used in balloons. Helium GAS is a common industrial chemical, but LIQUID helium is quite troublesome. When shipped from the US to Asia, half of the liquid helium would have evaporated and escaped, according to the same friend.

11. Helium is very light. Once it escapes into the atmosphere, it would leave the planet into outerspace, as it is so light that the Earth's gravity couldn't hold it in the atmosphere. It is not a renewable resource.

12. Helium is obtained from mining. Natural gas sometimes contain a little bit of helium, besides methane and other petroleum gases. United States is the largest supplier of Helium in the world.