# mass spectrometer questions

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#1
I have written some answers but some I'm not sure

How are the following processes achieved ?
Ionisation the sample ~>bombardment
Acceleration of the ions~> electromagnet
Deflection of the Ions..?

How could you find the molecular mass from the mass spectrometry = add up RAM values?

What is the mass spectrometers used for ?
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5 years ago
#2
The mass spectrometer is generally used to find RAM values for elements as well as RMM values. It can be used to analyse metals, diatomic elements and even compounds which produce a detector signal( usually written as % abundance ) against a mass to charge ratio.(m/z)

To calculate an RAM value, you multiply the percentage abundance of each isotope by the mass of the isotope and then divide by the total % abundance. For instance if you had 20% Carbon-12, 60% Carbon-14 and 20% Carbon-16 {These would never be the values but just an example} then the RAM of Carbon would be (20x12)+(60x14)+(20x16) all divided by 100.

Samples are first vaporised ( ie turned into a gas) and then ionised. There are different degrees of ionisation such as single charge and double charge. If sodium were put through the column, it would have a first ionisation of: Na(g)-->Na^+(g) + e^-. After this the sample is shot through another column and particles with the correct charge are attracted to the electromagnet whilst others are deflected or just miss. This is what produces the trace on the graph and this trace can be compared to those of known samples to see what the sample is made up of (ie identification by comparison)

Remember that mass spectrometry is mainly used for analytics which is why it is used by forensic scientists who can identify x10^-6 of drug samples and also fibres from clothes.

I hope this helps, this is a few of the basics and if you have any qs please ask!!

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