(666c) Novel Macroporous Adsorbents with Variable Functionalities: From Preparation to Application

Macroporous
chromatographic supports are ideal for preparative applications, where good
throughput, i.e. speed of separation, is required. In this regard, large
throughpores provide high bed permeability, which allows operation at high flow
rates.  Meanwhile, if these large pores are able to accommodate a fraction of
convective flow, so-called perfusive pores, then separation efficiency is
independent of the flow rate.

To this end, by
combining elements from colloidal and polymer reaction engineering, a novel
macroporous packing material with advanced mass transfer properties was
developed. Specifically, aggregation and breakage under flow of polymeric
microclusters allows the control final cluster size and pore size distribution,
while post-polymerization imparts high mechanical stability.

Owing to
surface-bound ATRP initiators a versatility of functionalities can be realized,
in order to employ different separation modes, relying on different types of
substrate-solute interaction. So far, conventional cation and anion exchange
chromatography have been addressed, as well as an alternative
temperature-responsive modality, where instead of ionic strength or polarity of
the mobile phase, temperature is utilized to control interactions. This is
advantageous from the environmental and cost-reduction viewpoint, as well as
for preserving bioactivity of the purified compounds.

As polymer
brushes are grafted from the substrate surface, multiple active sites are
available per unit area, offering increased binding capacities. Meanwhile, the
flexibility of such chains allows for favorable steric distributions, so that
large molecules like proteins, can be better accommodated.  As a matter of
fact, application examples demonstrate that our functionalized
adsorbents may compete with existing commercial chromatographic supports.

Figure 1.  SEM image of supporting microcluster.
White circles indicate large throughpores.

Figure 2.  Pore functionalization scheme.

Figure 3. Illustrative
separation of Lysozyme, α-Chymotrypsinogen and
Cytochrome-c (elution order) by an anionic-PE functionalized column versus a
commercial exchanger. Conditions: 30mM phosphate buffer pH7.0, linear gradient
elution from 0.0M to 1.0M NaCl (dashed line) at 1ml/min. Peak resolution was
calculated using the indicated formula.