What is the difference between mass specs?

[lord pickle]

Ok

So for school I am doing a project on mass spectrometers and I am aware of the fact that there are time of flight, sector, and quadropole mass specs. and I know how they work but what I want to know is why are there three different types? What are the advantages and disadavantages to a tof mass spec. versus a sector mass spec. versus a quadropole mass spec. ? I tried looking at the wiki article on mass spec. but it didn't have this info. Tried a google search but it links to papers that talk about some new fancy method of doing mass spec. and don't explain this basic question. So now I call out to the power of the internet and you frequency physics forums readers to help me answer this preplexing question.

Thanks

 

[SporadicSmile]

Well, I can't give you an overall comparison, but in the experiment I am part of we use a tof mass spec. The basic setup is that we are ionising molecules using photons, and then measuring the way in which the electrons are emitted, in a process called velocity map imaging. The details here arent really that important.

What we use the tof mass spec for is that we can measure a) what ions are being produced in our collisions, and b) in this setup we can measure the detection of an electron and an ion in coincidence, i.e. we can match an electron to the ion it came from. Thus, using the tof mass spec, we can see which electrons came from which molecule, which is a great advantage, for you can eliminate any electrons that are not from the molecule of interest during analysis of results.

Hope that at least in part helps.