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Analytical Spectroscopy Ii Question Paper

Analytical Spectroscopy Ii

Course:Master Of Science

Institution: Kenyatta University question papers

Exam Year:2009

KENYATTA UNIVERSITY
UNIVERSITY EXAMINATIONS 2008/2009
INSTITUTE OF OPEN LEARNING
EXAMINATION FOR THE DEGREE OF MASTER OF SCIENCE
SCH 555: ANALYTICAL SPECTROSCOPY II
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DATE: FRIDAY 14TH AUGUST 2009 TIME: 9.00 A.M. – 12.00 NOON
INSTRUCTIONS:
?? Attempt ALL Questions.
Q.1 a) i) Using a diagram, describe the process of electron impact ionization in
mass spectroscopy.
ii) Explain why most MS instruments have two different ionization
sources. (9 marks)
b) The MS spectrum for a particular compound possesses a strong parent peak at
m/e 122 (35%) plus peaks at m/e 92 (65%), m/e 91 (100%) and m/e 65 (15%).
In addition there are metastable peaks at 46.5 and 69.4 mass units.
Determine the structure of the compound. (8 marks)
c) Briefly discuss one type of geometry of double-focusing mass spectrometer.
(6 marks)
Total 23 marks
Q.2 a) i) NMR spectra are usually described in terms of chemical shifts and
spin-spin coupling. Explain how the two are useful in determining the
structure of a compound.
ii) At room temperature, NMR proton spectrum of methanol has no spinspin
coupling observed for the hydroxyl proton, but when the sample
is cooled to -40C, splitting occurs. Explain this observation and sketch
spectrum of the cooled sample. (12 marks)
b) Describe the appearance of the high-resolution proton NMR spectra of
acetone and acetic acid. (9 marks)
c) Explain how spin decoupling is used to interpret complex spectra. (5 marks)
Total 25 marks
Q.3 a) i) Explain the principle of analysis in magnetic susceptibility.
ii) Discuss the procedure of determining oxygen using its thermal
conductivity in a paramagnetic oxygen analyzer. (8 marks)
b) A natural product chemist isolated a compound active against malaria
from a plant and wants to determine its structure. Describe four
techniques the chemist will use and the information obtained form
each. (8 marks)
c) Using a diagram, explain how one example of a liquid
chromatography/mass spectrometry interface works. (5 marks)
Total 22 marks

Analytical Spectroscopy Ii Question Paper

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