... reasons:
• to avoid an undesirable change in separation due to a sample size that is too
large
• to increase detection sensitivity for trace analysis, by using the largest
possible sample size
• to maximize ... 1 to 4, the peak begins
to widen and then develops a flat top. For Equation (2.27) and the examples of
Figure 2.22, we assume the delivery of an undistorted (i.e., cylindric...
... directed to a photodetector, where it is monitored and
converted to an electronic signal for data processing. Because fluorescence is emitted
in all directions, it is common to monitor the emitted ... DETECTORS 169
lamp
filter or
monochromator
photocell
sample in
sample out
Figure 4.14 Schematic of a fluorescence detector. Dashed lines show optical path.
expensive fluorometers use filters...
... pack-
ing particles. To prevent particle aggregation, the interaction of the particle with the
slurry liquid should be stronger than interactions between particles. For example,
C
8
-orC
18
-modified particles ... as
illustrated by the cartoon of Figure 5.25a, the liquid may be acceptable. However, if
the particles tend to aggregate as in Figure 5.25b, the liquid is likely a poor cho...
... or embedded into individual
disks. The plate is analogous to a 8 × 12 array of miniaturized SPE cartridges.
The plates can be handled by robotic instrumentation to completely automate the
SPE ... poly-dimethylsiloxane or a polyacrylate [32, 33]. The fiber is dipped into the
solution to be analyzed, and analytes diffuse to and partition into the coating as a
function of their distribu...
... stream due to partially blocked column-inlet frit. (c)
Distortion of sample stream due to void at head of column.
0426 8121 0
Time (min)
(a)
(b)
Figure 17.19 Split peaks attributed to a partially ... way to flush particulate matter from the top
of the inlet frit and restore normal peak shapes. After reversing the column, flow 20
to 30 mL of solvent through the column to waste (not t...
... Hybrid Systems, 111
INTRODUCTION TO
MODERN LIQUID
CHROMATOGRAPHY
Third Edition
LLOYD R. SNYDER
LC Resources, Inc.
Orinda, CA
JOSEPH J. KIRKLAND
Advanced Materials Technology
Wilmington, DE
JOHN W. ... Lloyd R.
Introduction to modern liquid chromatography / Lloyd R. Snyder, Joseph J. Kirkland. – 3rd
ed. / John W. Dolan.
p. cm.
Includes index.
ISBN 978-0-470-16754-0 (cloth)...