Mass spec

Question 1

electro spray ionisation (ESI)

Answer 1

charged droplets of a solution leave the tip as a fine mist into the mass analyser

Question 2

desorption mass analyser (DESI)

Answer 2

electrospray sprayed at the sample thats adsorbed onto a surface and ionises the sample surface which goes into the mass analyser

gives more info and non-destructive

Question 3

MALDI

Answer 3

matrix assisted laser desorption/ ionisation

Question 4

tandem mass spec

Answer 4

• 1st mass analysis stage to select a precursor ion
• excites it causing it to fragment
• 2nd mass analysis stage to get mass of product ions

MS^2
can be tandem in space (happens in different regions in the instrument) and tandem in time
used for drug concentrations in hair

Question 5

isotope ratio mass spec

Answer 5

identifies elements due to their isotopes that exist within a more complex molecule
- identifies locations where people might have travelled based on drinking water in locations

Question 6

what are the 3 types of conclusions with hair evidence

Answer 6

association
inconclusive
exclusion