What's in a medicine- mass spectroscopy?


What is the molecular ion?

the heaviest ion on the mass spectrum, it is caused by the removal of an electron from the original molecule in the first stage of mass spectrometry 

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How does a mass spectrometer work?

1. Ionisation- the atom/molecule is ionised, this is done by knocking off one valence electron to give a positive charge, this occurs even if the molecule is likely to form a negative charge e.g a group one metal

2. Accleration- the resulting ions are then acclerated out of the ion source by an electric field

3. Deflection- charged particles are then deflected by a magnetic field, the amount an ion is deflected depends on its size and charge (the lighter the ion, the more it will be deflected, and the higher the charge the more it will be deflected)

4. Detection- as the ions are deflected, they are then detected by a computer, which then plots this onto a graph

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What is a fragmentation pattern?

the way in which the molecular ion breaks down- this is characteristic of a particular compound

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What is the base peak?

the most abundant ion that gives the strongest detector signal- it is given to be 100% intensity, and is used to compare with other intensities 

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Why might there be a M+1 peak?

due to the fact that there are some naturally occuring Carbon-13 isotopes-meaning that the compound could have a higher molecular mass 

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