Typical Examples For Determining Cscl Run Parameters - Beckman Coulter SW 32 Ti Instructions For Use Manual

SW 32 Ti and SW 32.1 Ti Swinging-Bucket Rotors
Preparation and Use

Typical Examples for Determining CsCl Run Parameters

Example A:
Starting with a homogeneous CsCl solution density of 1.40 g/mL and approximate particle buoyant
densities of 1.38 and 1.42 g/mL, at 20°C, where will particles band at equilibrium in the SW 32 Ti
rotor?
4
r
min
1
In Figure
volume (three-quarters full).
• The maximum allowable rotor speed is determined from the point where this curve
intersects the homogeneous CsCl density (28,000 RPM).
2
In Figure
3
Mark the point in
the selected run speed and temperature.
• Particles will band at these locations across the tube diameter at equilibrium during
centrifugation.
In this example, particles will band about 120 and 125 mm from the axis of rotation, about 5 mm of
centerband-to-centerband separation.
To determine interband volume in milliliters, use the following equation:
where r is the tube radius in centimeters and h is the interband separation in centimeters
Example B:
Knowing particle buoyant densities (for example, 1.55 and 1.50 g/mL), how do you achieve good
separation in the SW 32.1 Ti rotor?
1
In Figure
20
1
5 6
r
max
7
2, find the curve that corresponds to the required run temperature (20°C) and fill
3, sketch a horizontal line corresponding to each particle's buoyant density.
Figure 3 where each particle density intersects the curve corresponding to
5, sketch in a horizontal line corresponding to each particle's buoyant density.
2
3
V =  r
2
h
1. At Speed
2. At Rest in Rotor
3. At Rest Outside Rotor
4. Floating Components
5. Bands
6. Pelleted Material
7. Pathlength
EQ 7
LXL-TB-015BB