3
Resolution Comparison in Gradient Mobile
Phase Conditions
In Figure 2 the resolution of the Accucore XL 4 μm
HPLC column is compared to that of the fully porous 5
and 3 µm materials, using gradient mobile phase
conditions, and maintaining all other experimental
conditions for the 3 columns. The higher efficiencies
of the solid core 4 µm column results in improved
resolution: 27% and 11% higher resolution of
the critical pair over the fully porous 5 and 3 µm
columns, respectively. When using gradient mobile
phase conditions, efficiency cannot be used as a
measure of column performance; instead, peak width
or peak capacity are generally used. In Figure 3 the
peak capacities of the 3 columns are compared. The
Accucore XL 4 μm HPLC column shows 66% and 44%
higher peak capacity than the fully porous 5 and 3 µm
columns, respectively.
An even more significant improvement in resolution
with an Accucore XL C8 4 µm HPLC column is
demonstrated in Figure 4 for the analysis of 7 catechins.
Under the conditions adopted for this analysis,
resolution of greater than 2.6 was achieved for all
catechins on the Accucore XL C8 4 µm HPLC column.
On the fully porous C8 column, resolution between
the critical pair (peaks 4 and 5) was only 1.17, which
more than doubled with the Accucore XL C8 4 µm
HPLC column. The peak widths improved on average
by 34% when changing from the 5 µm fully porous to
the Accucore XL C8 4 µm HPLC column (Table 2).
This was achieved under the same chromatographic
conditions, with no changes in system configuration
and with a small backpressure increase, from 182 bar
with the 5 µm fully porous column to 241 bar for the
Accucore XL C8 4 µm column.
Figure 2: Comparison of the resolution of a critical pair (peaks 2 and 3) on fully porous 5 and 3 µm and Accucore XL 4 µm HPLC columns.
Experimental conditions: columns – C18, 150 x 4.6 mm; mobile phase – water and acetonitrile; gradient – 35% to 60% acetonitrile in
10 min; flow rate – 1 mL/min; column temperature – 30 °C; UV detection - 247 nm; injection volume – 5 μL
Figure 3: Peak capacity comparison for the herbicides method
120
20
0
40
60
80
100
Fully porous 5 µm
Fully porous 3 µm
Accucore XL 4 µm
Peak Capacity
1
Minutes
1
0
10
2
3
4
5
6
7
8
9
Rs = 2.47
Rs = 2.82
Rs = 3.13
2
3
4
5
6
7
1
2
3
4
5
6
7
5
6
7
1
2
3
4
Fully porous 5 µm
Fully porous 3 µm
Accucore XL 4 µm
1
Uracil
2
Tebuthiuron
3
Metoxuron
4
Monuron
5
Chlorotoluron
6
Diuron
7
Linuron
1...,31,32,33,34,35,36,37,38,39,40 42,43,44,45,46,47,48,49,50,51,...58