Peak Capacity - Agilent Technologies 1290 Infinity II 2D-LC User Manual

14 Theoretical Background
Theoretical basis of 2D-LC

Peak Capacity

Peak capacity may be differently defined:
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Geometrical The peak capacity may be defined as the maximum number of peaks that can be
Definition resolved in the available separation space. So peak capacity n
number of theoretical plates N:
( depends on the retention time range)
In practice peaks are usually not distributed randomly over the chromatogram
and often overlap. Or in other words: In practice peaks don't fill the available
separation space evenly. This is the reason, why the number of detectable
components of a sample in 1D-LC is relatively small.
2D-LC separation offers an alternative possibility for increasing n
retention mechanisms generate a separation plane. Thus, the peak capacity in
2D-LC is the product of the peak capacities of the individual columns. Due to
peak broadening in 1
two-dimensional ellipses on the retention plane.
How to calculate n
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2D-LC User Guide
As the maximum number of peaks that can be resolved in the available
separation space (Geometrical Definition), or
As the ratio of the total area of the chromatogram to the area required for the
resolution of any zone (General Definition)
st
and 2
depends on the method:
c
For comprehensive 2D-LC:
L = Separation space for dimension
ab = Area for rectangle circumscribing the ellipse on the separation plane
For heart-cutting 2D-LC:
nd
dimension, components in 2D-LC are present as
is related to the
c
: Orthogonal
c
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