Mass spectrometry 1 & 2 Flashcards
What are the basic steps in mass spec?
- Generate molecule ion gas phase
- Ionisation
- Mass seperation
- Ion detection
- Data interpretation
What si the most common form of ionisation?
Electron ionisation
What are the cons of EI?
- Hard ionisation
- Not always a clear molecular ion
- Fragmentation needed to solve molecular structure of complex molecules
- Difficult ot identify fragile molecules
What si the base peak?
tallest peak
Detection step is sensitive, minimum sample size for analysis. TRUE OR FALSE?
TRUE
Isotope disrtibution reveals the amount of Cl,Br, and C. TRUE OR FALSE?
TRUE
Isomers do not have the same masses. TRUE OR FALSE?
False
Every odd electron is an OE ion. TRUE O FALSE?
-TRUE
Rearrangements involving multiple bond breaking can also yield OE ions. TRUE OR FALSE?
TRUE
Formation of very samll ions unlikely. TRUE OR FALSE?
TRUE
Most stable ion is the largest peak (tertiary is more stable than secondary which is more stable than primary). TRUE OR FALSE?
TRUE
If ions are stable in solution, the same applies to gas. TRUE OR FALSE?
TRUE
Radicals are less stable with increased substitution. TRUE OR FALSE?
FALSE
Vinyl radicals are unstable. TRUE OR FALSE?
TRUE
If primary fragmentation leads to competition then loss of larger radical normal dominant. TRUE OR FALSE?
TRUE
What are the features for fingerprinting?
- Compare to database of spectra
- Needs to be established first
- Spectra specific for specific conditions
- EI mainly
- Other MS techniques much smaller databases
- Make own dedicated database of limited size
What is soft ionisation?
Only adds charge to molecule for easy identification of molecular ion (molecular mass)
-If you know the precice mas very well you can calculate the number of C,H,O,N,S
What does chemical ionisation do?
-Controls what functionality is ionised
Electrospray ionisation is very good for large biomolecules. TRUE OR FALSE?
TRUE
What solvents are used in ESI?
-MeOH/H20 mixtures
What are biomarkers used for?
- To identify biomolecules crucial for disease
- Undertsand disease more
- Identify target for treatment
- Effectiveness of treatment
- Routine detection of biomarkers using targeted, cheap and fast test
