Technical information

Centrifuge Standard Operating Procedure 4
Table 1-2: Rotor suitability for various applications applications (Basics of
Centrifugation, Cole Parmer Technical Library)
Type of
rotor
Type of Separation
Compatible
Tube Types
Pelleting
Rate
-
zonal
Sedimentation
Isopycnic
Fixed Angle Excellent Limited
Good for
macromolecules
Poor for cells
and organelles
Thick wall
open top and
thin wall
sealed
Swinging
Bucket
Inefficient Good
Good for cells
and organelles
Thick or thin
wall open top
Vertical
Not
suitable
Good Excellent
Thin wall
sealed
Rotor speed can be measured as revolutions per minute, RPM, or as relative
centrifugal force (RCF). RCF and RPM are related as per the following equation:
2
max
1000
17.11







RPM
RRCF
where R
max
is the maximum radius from the axis of rotation in centimeters. For
example, for a swinging bucket rotor, this would be the bottom of the bucket
when it is in a horizontal position.
1.3 Instrumentation
The J301 centrifuge operates under vacuum and the temperature can be set
between -20°C and 40°C. Each run can be set up manually, or run using a
preset program.
The ultracentrifuge can reach speeds up to 100,000 RPM depending on the rotor
used. There are three different rotors available for this instrument: a JS 13.1
swinging bucket, a JLA 10.500 fixed angle, and a JA 30.50 Ti fixed angle. The
JS and JLA rotors are composed of anodized aluminum and will corrode very
quickly if scratched, making them unusable, so treat these rotors with extra
care. The JA Ti rotor is composed of titanium and is less susceptible to
corrosion, but it should still be used and cleaned carefully.
Table 1-3 lists the properties of each rotor, and Table 1-4 lists the types of
tubes that can be used in each rotor. Note: Open top tubes should be filled
within 3 mm of the top to provide adequate support for the tube; only
thickwall tubes can be run at ½ full.