SEC
34
MULTI-PORE SIZE DISTRIBUTION IN A POLYSTERENE PACKING MATERIAL
Novel approach to GPC of samples with a wide range of molecular weights
Prior to the introduction of
TSKgel MultiporeH
XL
and
SuperMultiporeHZ
columns, scientists separating polymers with a wide range of molecular
weights were left with two options. One option is to use multiple
columns of different pore sizes linked together in series. A second is to
use a column packed with a mixed bed resin of different pore sizes at
an optimized mix ratio. However, problems can occur with both of these
methods, which include distortion of the chromatogram or deviations
between the actual calibration curve and the calibration curve
approximated from data obtained from the molecular weight standards.
As is shown in
FIGURE 27
, a novel approach to solve this problem
was developed by Tosoh scientists and is incorporated in TSKgel
MultiporeH
XL
and SuperMultiporeHZ Series columns.
These columns are packed with particles of uniform size synthesized
with a broad distribution of pore sizes. This novel approach creates a
linear calibration curve within each particle. Therefore, columns with an
extended linear calibration curve can now be prepared without mixing
particles of different pore sizes. This results in sharper peaks without
inflection points that may be observed using mixed-bed columns.
The pore size distributions of the TSKgel MultiporeH
XL
-M column
and a mixed-bed column are shown in
Figure 28
. The mixed-bed
column shows a sharp maximum for pores with a diameter of 0.08 µm,
though the overall pore size distribution ranges from 0.006 to 0.6 µm in
diameter. In the case of the TSKgel MultiporeH
XL
-M column, the pore
size distribution exhibits a wider maximum range from 0.02 to 0.1 µm
in diameter. This difference in pore size distribution may explain the
reason for the inflection phenomenon.
The small ID (4.6 mm) and length (15 cm) of the SuperMultiporeHZ
columns reduces solvent consumption and results in quick run times,
and offers high throughput capabilities.
Figure 29
demonstrates that
inflection points are no longer observed with semi-micro columns
packed from particles prepared by multi-pore technology.
TSKgel H series columns can be applied to analyse the molecular mass
distribution of a broad variety of organic-soluble polymers.
Table V
lists
the recommended solvents by application for TSKgel H series columns.
Super H columns are ideally suited to save analysis time and solvent
by semi-micro GPC. For optimum performance they should be used in
combination with a low dead volume GPC instrument such as the all-
in-one EcoSEC system.
Table VI
suggests optimum flow rates to be
applied for TSKgel SuperH and TSKgel H
HR
columns for various solvents.
figure 27
Strategies for wide range separation using SEC
figure 29
Comparison of TSKgel SuperMultiporeHZ-M and TSKgel SuperHZ for
separation of Acrylic resin
figure 28
Pore size distribution of TSKgel MultiporeH
XL
-M column and a mixed-
bed column
Large Pore Medium Pore Small Pore
Multiple Pore Size
Pure packings
with multi-pore size distribution
(TSKgel MultiporeH
XL
column)
Blend (mixed bed) packings
of different grades
(TSK-GEL GMH series)
Connect columns with
different grades of packings
(TSKgel G5000H+G4000H+G2000H)
Conventional Strategy
New Strategy
Strategies for wide range separation using Size Exclusion Chromatography
Pore size (µm)
Pore s ze distribution of TSKgel ultiporeH XL -M
col
and a mixed-bed column
0.001
0.01
0.1
1
10
0
1
2
3
4
5
Pore volume dV (log r)
TSKgel MultiporeH
XL
-M
Mixed-bed column
5
10
15
Elution time (minutes)
(A) TSKgel Su
(B) TSKgel Su
Mobile phase:
Detection:
Temperature:
Injection vol.:
Samples:
20
25
-5
5
15
mV
TSKgel SuperMultiporeHZ-M
TSKgel SuperHZ
(A)
(B)
Column: (A) TSKgel SuperMultiporeHZ-M,4.6 mm ID x 15 cm L, x 4;
(B) TSKgel SuperHZ4000+3000+2500+2000, 4.6 mm ID x 15 cm L x 4
Mobile phase: THF; Detection: RI; Temperature: 40°C; Injection vol.: 10 μL
Samples: acrylic resin
