1. Why is internal calibration possible for PMMA 3800?
The factory default calibration was known to be within half a Dalton theoretical masses can be assigned to many polymer peaks the terminal group information was known all of the above
2. Why can't you use one calibration for all polymers in this study?
calibration is mass dependent calibration depends on laser intensity the optimal instrument settings may be different all of the above
3. Which of the following is false?
reflectron mode is more sensitive for low mass polymers (<5000 amu) reflectron mode is less sensitive compared to linear mode only reflectron mode should be used to calibrate the instrument reflectron mode gives higher resolution than linear mode
4. What information could be derived from a good mass spectrum of MW average 3800?
monomer mass charge state degree of polymerization all of the above
5. Which one is the correct terminal group for PMMA 3800 in this case study?
-H and -H -H and Na+ -CH3 and -H -CH3 and -OH
6. Which of the following settings should not be used for a polymer with MW average >10,000?
higher delay time than low mass polymer linear mode higher low mass gate value than for a low mass polymer highest laser intensity
7. Which factor has the least effect on sensitivity (ion signal/amount)?
input band laser intensity laser shots delay time
8. Delay time effects
resolution sensitivity mass accuracy all of the above
9. Increasing the laser shots averaged from 16 to 256 should improve the S/N by?
4X, but with reduced resolution 4X 16X, but with reduce resolution 16X
10. What is the correct relationship between Mn, Mw and Mz for PDI ≠ 1?
Mn<Mw<Mz Mw<Mz<Mn Mz<Mw<Mn Mz<Mn<Mw
11. Which charge state is most common in maldi-tof MS?
0 1 2 >2
12 . Which of the following is the most reasonable mass-range that should be used to acquire a polymer mass spectrum with Mw = 3800 and PDI =1.2?
1000 to 6000 500 to 4000 3000 to 4600 3600 to 4000
13. What is the typical resolution (R=m/Dm at FWHM) you can achieve on the MALDI TOF-MS used in linear mode?
about R= 30,000 better than R=15,000 R= 200 to 3000 R=8000
14. Which scan mode gives the best mass accuracy?
Delayed extraction linear with delayed extraction reflector with delayed extraction combined linear and reflectron mode with delayed extraction
15. When using a laser intensity that is higher than optimal, which of the following is false?
Ion counts are greater Low resolution signal could become saturated mass range is extended