360 - Mass Spectrometry Flashcards
1
Q
What does a mass spec measure?
A
Molecular ass of compounds; mass to charge ratio (m/z) of ions
2
Q
Ion chromatogram
A
Signal intensity vs analysis time
3
Q
Mass spectrum
A
Signal intensity vs one m/z at one time pt
4
Q
Three types of ion chromatograms
A
TIC
BPC
XIC
5
Q
TIC
A
Total ion chromatogram
- ion chromatogram of all ions measured
6
Q
BPC
A
Base peak chromatogram
- intensity of the largest peak in a scan as function of time or scan number
7
Q
XIC
A
Extracted ion chromatogram
- ion chromatogram of only one ion
8
Q
Two major types of ionization techniques
A
Atmospheric pressure ionization (API)
Vacuum ionization
9
Q
API ionization
A
- one of the gentlest ionization types
- electro spray (ESI)
- atmospheric pressure chemical ionization (APCI)
10
Q
Electro spray
A
- form of liquid phase ionization
- compound of interest is already a charged ion in the liquid phase when it enters the ion source
11
Q
A gas phase ionization technique; neutral molecules in liquid phase need to be converted into gas phase in the ion source before ionization
A
APCI
12
Q
MALDI
A
- most popular vacuum ionization technique (esp. For bio molecule and large organic molecule ID)
- solid phase ionization technique
- sample mixed w matrix, sample is dried, newly formed crystals are ionized by a laser
