Download CHEM 380 PRACTICE EXAM III This exam covers: capillary

CHEM 380
PRACTICE EXAM III
This exam covers: capillary electrophoresis, CH 9 (mass spec), CH 3 (NMR), CH 4 (IR)
1. Fill in the blanks.
A) In capillary electrophoresis (CE), the term that describes the differential factor that allows the
separation of analytes is called the ______________________________________.
B) In CE, the movement of the mobile phase (usually a buffer) under the influence of a high voltage is
known as __________________________________.
C) Turning up the voltage in CE and can have the following positive effect: _____________________;
but can also have the following negative effect: ________________________________.
D) CE columns are usually made from ___________________. They are prepared by rinsing a basic
solution through them with causes _________________________________. These columns are
missing one of the very basic components of a chromatographic system, which is
______________________.
2. List the two methods of injecting a sample in CE and provide the disadvantage of each.
A)
B)
3. List two reasons why CE is a superb chromatography for large biomolecules.
A)
B)
4. Why does resolution improve as the inner diameter of the CE tube decreases?
5. What is the major disadvantage of using a small inner diameter capillary tube in CE and an absorbance
detector?
6. When using digital filters based on Fourier Transform filtering describe and sketch the result of using an
appropriate apodization function.
B) What distortion is possible if you are not careful with the size of the apodization function?
7. To the right is a free induction decay of an NMR
measurement. When this signal is processed using a Fourier
Transform, what shape will the signal peaks take? Why?
8. Draw and label a generalized diagram of a mass spectrometer.
9. What is m/z in mass spectrometry? Why must the analyte be careful not to assume the m/z = the ion
mass?
10. Draw a picture of a quadrupole mass selector. How does it separate ions by m/z? List advantages and
disadvantages.
11. Draw a picture of a X. How does it work? List advantages and disadvantages.
Where X=electron impact ionization, electrospray ionization, ion cyclotron resonance, MALDI, an
electric/magnetic field mass selector, MS/MS/MS, an electron multiplier, chemical ionization
12. Describe the difference between hard and soft ionization methods. Given one example of each method.
What advantage does each method provide?
13. What does the acronym NMR mean and what is the origin of the signal? Be specific about the essential
components.
14. What two signals are represented by the free induction decay? What do each signals turn into when the
raw data is Fourier transformed?
15. Explain the origin of chemical shifts and shielding. Why is it useful? Make sure you differentiate
between upfield and downfield.
16. Why is it useful for NMR sample solvents to be deuterated? What does this mean?
17. Why are powerful NMRs (200 MHz and above) expensive to maintain?
18. The visible spectrum ends at 750 nm. Convert this to wavenumbers.
19. What are the three regions of the IR spectrum and why are they useful?
20. What makes a compound IR active? Why?
21. Draw the relationship between electronic, vibrational, and rotational quantum states.
22. How does an interferometer work? What is the Fourier transform relationship? Provide the two units.
23. What is the Fourier transform relationship in NMR? Provide the two units.
24. How does an ion cyclotron resonance mass selector work? What is the Fourier transform relationship?
Provide the two units.