WEEK4

Question 1

Homolytic cleavage

Answer 1

-1 electron shift
-bond 2 positions away from the functionalized atom
-methyl-radical is formed
-odd fragments (no N in molecule)

Question 2

Heterolytic cleavage (or inductive)

Answer 2

-Halogens, ethers, thio-ethers
-2 electron shift (e attracted by the functional atom)
-bond directly neighboring the
-functionalized atom is cleaved
-carbocation is formed
-odd fragments (no N in molecule)

Question 3

McLafferty rearrangement

Answer 3

-transfer of H-atom (proton+e)
-followed by a homolytic fragmentation
-even fragments (no N in molecule)
-molecule needs to be big enough

Question 4

N-rule: even or odd masses

Answer 4

N-containing molecules regularly have odd masses (even fragments)

Question 5

N-rule in case of fragmentation

Answer 5

Homolytic=Mw even-fragments odd
Heterolytic=Mw even=fragments even

Question 6

Working mechanisms of MS; ION SOURCES

Answer 6

1.Electron ionisation
2.MALDI
3.ESI

Question 7

Working mechanisms of MS; Mass separation

Answer 7

1.Quadrupol
2.TOF

Question 8

MALDI

Answer 8

Matrix-assisted laser desorption-ionization

Question 9

TOF

Answer 9

Time of flight