An Extended Range of Columns for Aqueous Size Exclusion Chromatography

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An Extended Range of Columns for Aqueous Size
Exclusion Chromatography
Inspiring Excellence
Greg Saunders, Graham Cleaver and Ben MacCreath,
Varian, Inc., Church Stretton, Shropshire SY6
6AX, UK
PL aquagel-OH Range for Aqueous SEC The use of
SEC for the analysis of aqueous polymers is of
growing interest. However, this application area
is challenging due to the number of ionic and
hydrophobic interactions that can occur when
analyzing water soluble materials. PL aquagel-OH
columns have been specifically designed to allow
the analysis of materials of this kind. Simple
modification of the eluent minimizes interactions
and ensures that pure size exclusion
chromatography is obtained.
Introduction Size exclusion chromatography (SEC),
also known as gel permeation chromatography
(GPC), is an important analytical technique in
the field of polymer analysis. Using SEC, samples
of polymer are separated on the basis of size in
solution. Assuming an appropriate calibration is
performed or specific information-rich detectors
are selected, the size separation can be
converted into a molecular weight separation -
key information in describing the physical
behavior of the polymer. Aqueous SEC is used for
the analysis of water-soluble polymers. Recently,
there has been increasing interest in this area
as the development of biodegradable and
environmentally friendly materials has grown.
Typically, SEC columns for aqueous applications
require packing materials with highly hydrophilic
surfaces that are compatible with water and
buffers. Particle sizes must be tailored to allow
high-resolution separations to be performed
without undue increase in column backpressure
that can lead to shearing effects and can reduce
the column lifetime. Finally, as the range of
applications grows a very large array of columns
is required to cover all possible sample types
across the range.
This poster describes an extensive family of
columns for aqueous size exclusion
chromatography. The columns are packed with
materials of high hydrophilicity to ensure pure
SEC is obtained for the widest range of samples,
including anionic, cationic and hydrophobic
types. Being available in many particle and pore
sizes, this newly completed range of columns
represents a versatile solution to aqueous SEC.
Typical Standard Separations The PL aquagel-OH
range of columns can be calibrated in aqueous
eluents by the use of polyethylene glycol and
oxide (PEG/PEO) standards, or with pullulan
polysaccharaides. PEG/PEO standards are suitable
for a wide range of applications, whereas the
polysaccharide standards are more suited to the
analysis of biological sugar-based materials as
they are similar in structure and therefore give
more realistic results.
Size Exclusion Chromatography SEC is a technique
used for the separation of macromolecules on the
basis of their size in solution. A sample is
introduced into a flow of solvent passing through
a column packed with porous beads. As the
molecules pass down the column they are able to
diffuse in and out of the pores, dependent on
their relative dimensions. As a result, smaller
molecules, (lower molecular weight) are retarded
in eluting from the column compared to larger
molecules (higher molecular weight). Thus a size
separation is obtained.

• Features of the PL aquagel-OH range
• pH range 2 10
• Compatible with 50 methanol
• High mechanical stability
• 8 µm columns for analytical work
• 15 µm for high viscosity polymers
• 5 µm for high resolution analysis

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Characteristics of the full PL aquagel-OH Range
Typical applications The PL aquagel-OH range of
columns covers applications across the molecular
weight resolving range. Heparin is a
highly-sulfated glycosaminoglycan with a low
molecular weight which acts as an anticoagulant.
The molecular weight of Heparin influences the
clotting of the material. PL aquagel-OH columns
may be used to distinguish different batches of
this material. Pectin is a structural
polysaccharide found in the walls of cells. It is
extracted from citrus fruits and used as a
gelling agent in food. Molecular weight is a key
parameter of this material, controlling the
viscosity properties.
Chitosan is a polysaccharide produced from
chitin, the main component of crab shells.
Chitosan has received interest due to its
susceptibility to biodegradation. A cationic
material, chitosan must be dissolved in
concentrated acid for analysis and must be
analyzed at low pH to obtain good chromatography.
Polyacrylamide is a synthetic polymer that has
uses as a thickening agent and in gel
electrophoresis. Generally a high molecular
weight material, the analysis of polyacrylamide
requires large particle size columns due to the
viscosity of the material. Hyaluronic acid is a
naturally occurring polysaccharide that is
extracted from the combs of roosters. Used in eye
surgery due to its superior viscosity properties,
the molecular weight distribution is critical to
the medical application of this material.
Summary The analysis of water-soluble polymers by
SEC is difficult due to the number of ionic and
hydrophobic polymers that can be dissolved in
water. The PL aquagel-OH column range is an
extensive selection of columns specifically
designed for the analysis of water-soluble
polymers. Available in a range of pore and
particle sizes, the PL aquagel-OH range provide
solutions for all aqueous SEC appications.
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