Zonal Density Gradient Reorientation

Gradient materials are loaded while the rotor is at rest, the flow is stopped and a linear density gradient is formed while the rotor is accelerating to a set speed.  Following a reorientation phase the gradient transitions from horizontal to vertical in the rotor.  After this transition occurs then the rotor can be accelerated to set speed while in a continuous flow operation.

Zonaldensity gradient reorientation

Step Process
1 The density gradient is loaded into the rotor while it is at rest.
2 As the rotor is gradually accelerated, the gradient reorients vertically inside the rotor assembly.
3 Once at the required operating speed, sample fluid is pumped into the rotor on a continuous flow basis.
4 The sample particles sediment radially into the linear density gradient. The particles band (iso-pycnically) in cylindrical zones where the gradient density equals a particle's buoyant density.
5 At the end of the run, the rotor is decelerated to rest.
6 During deceleration the gradient reorients itself to the original position without loss of resolution in the particle bands.
7 The banded particles are now ready to be unloaded. Fractions are collected using the Automated Fluid Handling System.
KII Manufacturing Scale Ultracentrifuge

Our Mission

To be the supplier whose singular purpose is the support of bioprocess and pharmaceutical industries by providing expertise in continuous flow UCF separation applications and now fluid handling solutions.

Contact Us


Alfa Wassermann Inc . 4 Henderson Drive
West Caldwell . NJ 07006 . USA

Telephone +1 800 220 4488
Fax +1 973 276 0383


Alfa Wassermann B.V. Lorentzlaan 5
3401 MX IJsselstein . Netherlands

Telephone +31 348 487 300
Fax +31 348 433 000

Contact Us