課程名稱︰分析化析乙下
課程性質︰
課程教師︰林萬寅
開課系所︰
考試時間︰2004.6.15
試題 :
1. Two molecules A and B were separated with a chromatographic column of
length 25cm and yeilded the following results:
Compound retention time(min) W1/2(min)
A 12.5 0.20
B 14.0 0.25
(a) Find the number of theoretical plates for compound A.
(b) Find the plate height for compound B.
(c) Find the resolution between the two peaks for compounds A and B.
2. (a) Explain the difference between wall-coated, support-coated, and
porous layer open tubular columns fo GC.
(b) What is the advantage of a bonded stationary phase in GC?
(c) Why do we use a makeup gas for some GC detectors?
3. A capillary electrophoresis is set up with the injector end negative
and the detector end positive at pH 3.0.
(a) What order will cations, anions, and neutral molecules be eluted?
(b) Are the anions moving with or against the electroosmotic flow?
(c) If the pH is raised to pH 8.0, how will the electroosmotic flow
change?
4. The molar absorptivity is 4000M^-1cm^-1 for an acid HA and 12000M^-1cm^-1
for its conjugate base A- at 400nm. A 1.0x10^-4 M HA solution at pH 6.0
in a 5.0-cm cell gave an absorbance of 1.0 measured at 400nm. Calculate
Ka for this acid.
5. What are the principal sources of band broadening in (a) capillary zone
electrophoresis and (b) micellar electrokinetic CE? Sketch what you
expect the van Deemter curve to look like for both CE modes?
6. Explain the following terms.
(a) split injection in GC
(b) Flame ionization detector for GC
(c) Indirect detection in CE
(d) Suppresed-ion chromatography
(e) Hollow-cathode lamp in AA
(f) Deactivation processes for excited molecules
(g) Solid-phase microextraction
(h) Zeeman correction for AA
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