15:16given by the equationIntroduction to Chromat...R₁ = VN (-1) (-₂)4where k'g is the capacity factor of the slower moving species anda is the selectivity factor.221+kBaN = 16R² ² (1+)²α-1,6730 May 202318This equation can be rearranged to give the number of platesneeded to realize a given resolution:4G|| 25 82196830 May 2023Effect of Resolution on Retention TimeAs mentioned earlier, the goal in chromatography is thehighest possible resolution in the shortest possibleelapsed time.Unfortunately, these goals tend to be incompatible;consequently, a compromise between the two isusually necessary.The time (t) required to elute the two species inFigure above with a resolution of Rs is:216R²u(ER) B = 16A ² (__) ² (1+ku) ²(KB)where u is the linear velocity of the mobile phase.672068ExampleSubstances A and B have retention times of 16.40and 17.63 min, respectively, on a 30.0-cm column.An unretained species passes through the columnin 1.30 min. The peak widths (at base) for A and Bare 1.11 and 1.21 min, respectively. Calculate (a)column resolution, (b) average number of plates inthe column, (c) plate height, (d) length of columnrequired to achieve a resolution of 1.5, and (e) timerequired to elute substance B on the longer column.Answer

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Substances A and B have retention times of 16.40 and 17.63 min, respectively, on a 30.0-cm column. An unretained species passes through the column in 1.30 min. The peak widths (at base) for A and B are 1.11 and 1.21 min, respectively. Calculate (a) column resolution, (b) average number of plates in the column, (c) plate height, (d) length of column required to achieve a resolution of 1.5, and (e) time

Substances A and B have retention times of 16.40 and 17.63 min, respectively, on a 30.0-cm column. An unretained species passes through the column in 1.30 min. The peak widths (at base) for A and B are 1.11 and 1.21 min, respectively. Calculate (a) column resolution, (b) average number of plates in the column, (c) plate height, (d) length of column required to achieve a resolution of 1.5, and (e) time

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Concept explainers

Mass Spectrometry

This process is an instrumental method in which a sample is changed to fast moving positive ions by electron bombardment. The charged particles vary due to their different mass to charge ratio and are estimated with the help of this difference. It is also called mass spectroscopy.

Question

15:16
given by the equation
Introduction to Chromat...
R₁ = VN (-1) (-₂)
4
where k'g is the capacity factor of the slower moving species and
a is the selectivity factor.
2
2
1+kB
a
N = 16R² ² (1+)²
α-1,
6730 May 2023
18
This equation can be rearranged to give the number of plates
needed to realize a given resolution:
4G|| 25 82
19
6830 May 2023
Effect of Resolution on Retention Time
As mentioned earlier, the goal in chromatography is the
highest possible resolution in the shortest possible
elapsed time.
Unfortunately, these goals tend to be incompatible;
consequently, a compromise between the two is
usually necessary.
The time (t) required to elute the two species in
Figure above with a resolution of Rs is:
2
16R²
u
(ER) B = 16A ² (__) ² (1+ku) ²
(KB)
where u is the linear velocity of the mobile phase.
67
20
68
Example
Substances A and B have retention times of 16.40
and 17.63 min, respectively, on a 30.0-cm column.
An unretained species passes through the column
in 1.30 min. The peak widths (at base) for A and B
are 1.11 and 1.21 min, respectively. Calculate (a)
column resolution, (b) average number of plates in
the column, (c) plate height, (d) length of column
required to achieve a resolution of 1.5, and (e) time
required to elute substance B on the longer column.
Answer

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