Week 2

Question 1

Sof ionization : positive mode
Whats that plus equation

Answer 1

Adoption of proton
M+H+=[M+H]+
M+1=[M+1]+

Question 2

Soft ionization: negative mode
Definition plus equation

Answer 2

Release of proton
M-H+=[M-H]-
M-1=[M-1]-

Question 3

Which atom ionizes?

Answer 3

Ion-dipole interactions most likely to occur (forced interactions)

Question 4

In positive mode happens

Answer 4

-H+ interacts with delta negative atoms, like O or N
-Compounds possessing basic characteristics

Question 5

In negative mode

Answer 5

-Molecules can deprotonate
-Molecules with acidic functional groups
-Hydroxyl-groups

Question 6

Hard ionization summary

Answer 6

An electron is stripped from a molecule [M+]
Creating a positively charged cationic radical, that is unstable, molecule falls apart, gives fragments
mass ionized molecule=mass molecule (mass electron is neglectable)
Often applied after the GC separation, hardly applied in combination with HPLC

Question 7

Soft ionization summary

Answer 7

molecule accepts or donates a proton [M+H]+ or [M-H]-
creating a positive or negative charged molecule
mass ionized molecule=mass molecule+or-1
ionized molecule is stable-direct info about the mass of the molecule, fragmentation is possible by adding extra energy
method of choice after the HPLC separation