8.1 Mass Spectrometry

Question 1

1. sample injection

Answer 1

dilute solution sample injected into a receptor, then nebulized into gaseous form

Question 2

2. ionisation

Answer 2

sample is hit with high-energy electron beam, forming 2 positive ions (one from beam, one hit off)

Question 3

3. acceleration

Answer 3

molecular ion, positive charge is accelerated in an electric field

Question 4

4. deflection, separation

Answer 4

stream of ions is deflected by magnetic field located along bend in the tube

separates ions based on their mass-to-charge ratio (m/z). lighter ions will be more bent

Question 5

5. detection

Answer 5

ions hit a detector which converts ion arrival into electrical signal, which is amplified and recorded on a mass spectrum

Question 6

what is molecular ion peak

Answer 6

singly charged ion, m/z ratio is the same as relative molecular mass

Question 7

what is base peak

Answer 7

most abundant fragment ion

Question 8

general formulae of alkane, alkene, alkyne

Answer 8

alkane Cn H(2n+2)
alkene Cn H(2n)
alkyne Cn H(2n-2)

Question 9

general formula of alcohol

Answer 9

Cn H(2n+2) O

Question 10

general formula of haloalkane

Answer 10

Cn H(2n+1) X

Question 11

general formula for aldehyde and ketones

Answer 11

Cn H(2n) O

Question 12

general formula for carboxylic acid and ester

Answer 12

Cn H(2n) O2

Question 13

general formula for primary amine and amide

Answer 13

amine Cn H(2n+3) N
amide Cn H(2n+1) ON

Question 14

relative m/z of molecular ion containing certain isotopes is proportional to

Answer 14

relative isotopic frequency