Mass spec

Question 1

Vaporisation

Answer 1

Sample must be a gas before injected to spectrometer.

Question 2

Ionisation

Answer 2

Sample bombarded with high energy electrons to create positive ions. Molecules can also fragment here.

Question 3

Acceleration

Answer 3

High electrical field accelerates positive ions to be all at same velocity.

Question 4

Deflection

Answer 4

Strong magnetic field made by electromagnet deflects ions. Heavier ions less deflected, this sorts ions into mass.

Question 5

Detection

Answer 5

M/z ration calculated for each positive ion and the relative abundance of each type of ion is calculated relative to the most abundant ion.

Question 6

Order of processes in mass spec

Answer 6

Vaporisation, ionisation, acceleration, deflection, detection

Question 7

Things must be able to explain

Answer 7

Calculate relative atomic mass from relative abundance. Predict and explain peaks. Isomers. Use M+ peaks to acknowledge isotopes and to help explain structure.