Postnova analytics
Dr. Thorsten Klein founded Postnova
Analytics GmbH, following his Ph.D. in 1997. He was driven by the idea
of building a company with a powerful and innovative product portfolio
made for scientists working in the area of biotechnology, polymer and
particle research.
Initially, Postnova introduced the world's first totally integrated
automatic and complete Asymmetrical Flow-FFF (AF4) system. Postnova attained its next milestone at the
end of 1998 when it presented the first FFF system with on-line coupling
to DLS detection for high resolution and fast particle and polymer
characterization. These innovations were followed with their own modular
laser multi-detector, incorporating static and dynamic laser light
scattering. Then Postnova invented the world’s first High Temperature
Asymmetric Flow FFF and also the first commercial mid Temperature
Asymmetric Flow FFF.
Originally based in downtown Munich, Germany, in the Munich Center of
Technology. they moved in 2003 into new headquarters
in the City of Landsberg in southern Germany
There are several possible forces that
can be used to
fractionate particles in flowing systems (FFF) and these include
Thermal, Flow proper, Sedimentation forces (with or without
centrifugation) and more esoterically electrical.
With classic ASFFF the forces that operate can be summed up in
the diagram on the bottom right.
A cross flow force is applied from a liquid being moved at right
angles to the sample flow.
What they all do is provide fast, high
resolution separtion of particles by size...detection can be by
DLS, UV or RI. |
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Differently sized particles with
varying diffusion coefficients are separated by the velocity
gradient inside the channel. After the injection the particles/
polymers are forced in the direction of the lower membrane by
the cross flow. The cross flow leaves the channel through this
membrane, whereas particles and polymers are rejected by the
membrane. Smaller particles will diffuse back into the channel
further than larger particles because of their larger diffusion
coefficients. As a result smaller particles are located in the
area of faster channel flow stream lines inside the channel and
in this way will be eluted from the channel before larger
particles, that are located in slower stream lines and eluted
later.
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