Mass Spectrometry

Question 1

What is Mass Spec?

Answer 1

A machine is involved. Blasts off different daughter fragments of molecules to measure. Adds up to total compounds mass. I’ll juili look

Question 2

What is a daughter ion?

Answer 2

An electrically charged product of reaction from a particular parent ion. A segment from the full compound.

Question 3

What does m/e 15 show?

Answer 3

CH3

Question 4

What is at m/e 29?

Answer 4

CH3CH2+

Question 5

What is at m/e 43?

Answer 5

CH3CH2CH2+ / CH(2 CH3’s attached) / CH3 — =O +

Question 6

What is at m/e 77?

Answer 6

Benzene ring!

Question 7

What is at m/e 91?

Answer 7

Mono substituted benzene or tropylliumion (seven sided ring)

Question 8

What is at m/e 105?

Answer 8

Mono substituted Benzene with aldehyde

Question 9

What is the very furthest peak to the right?

Answer 9

The parent ion! The total mass of the molecule!

Question 10

What is the (M+1) Peak?

Answer 10

M+ - parent
(M+ 1) is 13C

Height M+1
(—————-) % = 1.1 x # of carbons
Height M

Question 11

What is special about mass spec?

Answer 11

It is always a plus charge on every daughter ion!

Question 12

How do alcohols work on mass spec?

Answer 12

They frequently do not give you an M+ they give you (M-H2O)+
Water weights 18 so (M-18). Alcohols dehydrate

Question 13

High res mass spec?

Answer 13

Gives more decimal points. More accurate. Only corresponds to a specific molecule.