Spectroscopy Showcase @ UEA (Mon 18th July 2011)
The AS Chemists had a tour of the analytical facilities at UEA, Norwich.
They got to see:
> the UV-Vis spectroscopy
Used to looked at coloured compounds and indicators that change colour (that's the "vis" part of the electromagnetic spectrum). It can even be used to quantify how much you've got - using a method that we study at A2 called the "callibration-curve" method.
It can also be used to check out the presence and amount of compunds that absorb Ultra-Violet radiation (like benzene), that look like water to the human eye. This is a much more common use of the technology according to our demonstrator (ex-Hartismere student Jamie Conyard).
> Infra-red spectroscopy
Good for identifying covalent bonds in organic molecules like ethanol and caffeine. When exposed to IR radiation, bonds absorb some if it and either vibrate or stretch. This missing radiation is detected and recorded.
> NMR
A bit like MRI scans in hospitals. NMR uses a very powerful magnet to make protons in the nuclei of hydrogen atoms spin. The magnets have to be "super-cooled" using a combination of liquid nitrogen and liquid helium to allow their components to superconduct. The spinning nuclei can be detected to build up a picture of the molecule. Of the 5 NMR machines that we saw, the 500 megahertz device was the most sensitive, upto 30 times more so than a hospital NMR.
>Mass Spectrometry
A destructive technique (the sample is destroyed during use). Mass spec uses a laser (low power) to remove electrons from the target molecule. The charged molecule is then fired through a accelerator and hits a detector. Heavy ions reach the detector more slowly......