Page 173 - An Introduction to Analytical Atomic Spectrometry - L. Ebdon

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5 (a) Discuss the importance of the temperature of the atom cell in atomic emission spectrometry and
in atomic absorption spectrometry.
(b) Describe how the requirements of the monochromator and detection system differ in atomic
emission and atomic absorption spectrometry.

6 With regard to both theoretical principles and practical considerations of inductively coupled
plasma atomic emission spectrometry, discuss the design of two of the following:
(a) nebulizer systems;
(b) the plasma;
(c) monochromators and detector systems.

7 Describe suitable instrumentation for sensitive analytical measurements in atomic absorption
spectrometry. Include a discussion of the ways in which the atomic population in the atom cell may be
maximized and why the light source is always a line source.

8 In analytical atomic spectroscopy, how are atomic populations usually formed from solutions? In
your answer, include an outline of the conventional apparatus and basic processes involved, and explain
how the atomic or ionic population may be maximized.

9 Discuss why the following are often preferred for practical atomic absorption spectrometry:

(a) a modulated narrow line source;
(b) a Czerny-Turner monochromator;
(c) a small graphite tube atomizer;
(d) microprocessor controlled curvature correction.

10 Discuss the reasons for the following:
(a) Compared with flame atomizers, electrothermal atomizers generally result in enhanced sensitivity
for atomic absorption spectrometry.
(b) Increasing the intensity of the source increases the sensitivity in atomic fluorescence spectrometry,
but has relatively little effect in atomic absorption spectrometry.
(c) Compared with flame atomizers, plasma atomizers generally result in enhanced sensitivity for
atomic emission spectrometry.
(d) Metals dissolved in organic solvents can show either enhanced or reduced sensitivity compared with
those in aqueous solution.

11 Describe a typical electrothermal atomizer for atomic absorption spectrometry. Critically compare
graphite furnaces, air-acetylene flames, and nitrous oxide flames as atom cells for atomic absorption
spectrometry.