Analytical instrument questions

[Wizard]

Hey guys, just trying to understand how the instruments actually work.

In AAS, what is the point of vapourising the sample? I know that it makes it gaseous, but why should it be gaseous - why not solid?

Also, I have seen the data booklet, and noticed that many non-polar bonds are not present. I was wondering if IR spectrophotometers only picked up bonds which are polar. 

[shinny]

Also, I have seen the data booklet, and noticed that many non-polar bonds are not present. I was wondering if IR spectrophotometers only picked up bonds which are polar. 

Yep, IR doesn't work on non-polar bonds. Because IR works on measuring the energy released as a result of twisting of bonds and such, it doesn't work on non-polar bonds simply because these don't twist.

[Mao]

the metal you are analysing are in solution as cations before running through the AAS. These are vaporised and in the process, reduced to ground state so light can be absorbed by these metal atoms.

[mark_alec]

it doesn't work on non-polar bonds simply because these don't twist.

I disagree. Something as simple as ethane (the C-C bond is non-polar) is known to have different conformations based on the fact that it can freely twist.

[shinny]

It might depend on what links on to that C-C bond. What I said above only works if it's a symmetrical non-polar bond, such as that in O=O and such.

[Wizard]

Also, with flame tests and AES, how do cations and anions fit into the equation. I know that atoms in the ground state absorb lenergy of a specific wavelength, and go to the excited state, and when it returns to the ground state, it releases light, but does this also apply to anions and cations? (will they absorb and emit light?)

[Mao]

in the flame, ions are reduced to ground state.

[Wizard]

Oh yeah, lol, Thanks for the help!

[mark_alec]

It might depend on what links on to that C-C bond. What I said above only works if it's a symmetrical non-polar bond, such as that in O=O and such.

O=O doesn't rotate due to the bonds (think of them as sideways attaching bonds in a plane, that prevent the atoms from twisting with respects to each other)

[Wizard]

What are some conceivable errors in UV Visible Spectroscopy? And is the sample cell made out of glass or something else?

[Wizard]

And what is a blank solution? Is it just solvent in a samle cell?