Technical Note 20742
Improving Analysis Sensitivity
with Solid Core 4 µm Columns
Luisa Pereira, Eilidh MacRitchie, Thermo Fisher Scientific, Runcorn, Cheshire, UK
Introduction
Sensitivity is often an important characteristic of a
method that needs to be considered in the method
optimization strategy. The chromatographic parameters
that affect sensitivity are column length and diameter,
column performance (peak shape and efficiency),
thermodynamic parameters (retention time and
temperature), and injection conditions. Sensitivity is
related to the concentration at the peak apex C
max
, which
depends on the chromatographic parameters as described
by Equation 1 [1].
Where
ε
t
– the total column porosity
L – column length
d
c
– column diameter
N – peak efficiency
k – peak retention factor
c
0
– sample concentration
V
i
– injection volume
T
f
– peak tailing factor (measured at a given peak
height fraction h)
κ
– constant dependent on h
From Equation 1 it is clear that high efficiency and
symmetrical peaks produce higher response peaks (higher
C
max
) and therefore higher sensitivity. C
max
is also inversely
proportional to column porosity; thus, lower porosity
columns such as those packed with partially porous
particles should also produce higher C
max
, assuming all
other conditions remain unchanged.
Key Words
Solid core, fused core, superficially porous, sensitivity, signal-to-noise,
efficiency
Abstract
In this technical note the sensitivity, measured as signal-to-noise ratio,
achieved with solid core 4 µm particle packed columns is compared to that
of fully porous 5 and 3 µm particle packed columns.
Based on Core Enhanced Technology™ using 4 μm solid
core particles, Thermo Scientific™ Accucore™ XL HPLC
columns allow users of conventional HPLC methods to
obtain performance far beyond that of columns packed
with 5 μm or even 3 μm fully porous particles. Using solid
core 4 μm particles packed in conventional column
dimensions, significant improvements in the assay
performance can be achieved without the need to make
changes to the operating parameters or system
configuration. Very high peak efficiencies using standard
HPLC instrumentation and conditions allow for increased
peak resolution and limits of detection.
C
max
=
ε
t
π √
2
π
4
L (1+k)
d
c
√
N
(
T
f
– 1)
κ
c
0
V
i
2
1...,39,40,41,42,43,44,45,46,47,48 50,51,52,53,54,55,56,57,58