3.2.2.4 Preparatory Investigations
In a first set of experiments, the interactions of PE and PP with the stationary phase
Hypercarb were investigated. The samples were dissolved in 1-decanol at 160
C
and then injected into the column that was kept at the same temperature. The
sample solvent was used as the starting mobile phase. A linear gradient starting
from 100 % 1-decanol and going to 100 % TCB was employed later to achieve
separation (the start of the gradient is marked in the chromatograms). The separation of linear PE standards and iPP with varying average molar masses is shown in
Fig. 3.22. iPP is not retained and elutes before the start of the gradient in the SEC
mode (Fig. 3.22a). PE adsorbs on the column from 1-decanol (starting composition
of gradient). The introduction of TCB in the mobile phase promotes desorption of
PE and elution takes place with respect to the molar mass of the corresponding PE
(Fig. 3.22b).
The given chromatographic conditions work perfectly for the separation of
binary blends of iPP and PE, as can be seen in Fig. 3.23 for combinations of
Fig. 3.22 Overlay of
chromatograms for iPP (a)
and PE (b). Column:
Hypercarb. Mobile phase:
1-decanol and linear gradient
from 0 % to 100 % TCB in
10 min. Flow rate: 0.5 mL/
min. Temperature: 160
C
(reprinted from [89] with
permission of J. Wiley &
Sons)
3.2 Solvent Gradient Interaction Chromatography
103
In a first set of experiments, the interactions of PE and PP with the stationary phase
Hypercarb were investigated. The samples were dissolved in 1-decanol at 160
C
and then injected into the column that was kept at the same temperature. The
sample solvent was used as the starting mobile phase. A linear gradient starting
from 100 % 1-decanol and going to 100 % TCB was employed later to achieve
separation (the start of the gradient is marked in the chromatograms). The separation of linear PE standards and iPP with varying average molar masses is shown in
Fig. 3.22. iPP is not retained and elutes before the start of the gradient in the SEC
mode (Fig. 3.22a). PE adsorbs on the column from 1-decanol (starting composition
of gradient). The introduction of TCB in the mobile phase promotes desorption of
PE and elution takes place with respect to the molar mass of the corresponding PE
(Fig. 3.22b).
The given chromatographic conditions work perfectly for the separation of
binary blends of iPP and PE, as can be seen in Fig. 3.23 for combinations of
Fig. 3.22 Overlay of
chromatograms for iPP (a)
and PE (b). Column:
Hypercarb. Mobile phase:
1-decanol and linear gradient
from 0 % to 100 % TCB in
10 min. Flow rate: 0.5 mL/
min. Temperature: 160
C
(reprinted from [89] with
permission of J. Wiley &
Sons)
3.2 Solvent Gradient Interaction Chromatography
103