Multiply the performance of the conventional centrifuge by 20 and you have a centrifugal wallop that can accom plish in 90 minutes at 40,000 rpm, separations requiring more than a full working day at 17,000 rpm. Such extreme centrifugal forces are available to you routinely with the Spinco Model L Preparative Ultracentrifuge. Molecules of nearly identical mass can be separated efficiently...very small particles sedimented... macromolecules sorted for further studies. Adding to the versatility of the Model L are nine interchangeable rotors. Among them you'll find a com bination of speeds, forces, tube angles and capacities to make your preparative work faster and more efficient. Accessories —such as quartz tubes for the swinging bucket rotors for direct absorption studies, and a Tube Slicer for precisely isolating fractions from cellulose tubes —further extend the usefulness of the Model L. For more details, write Spinco Division, Beckman Instruments, Inc., Stanford Industrial Park, Palo Alto, California, for information file L-7A.
Beckman
S p i n c o Division Beckman Instruments,
General-Purpose
Fixed-Angle
Rotors
TYPE 21: Large capacity makes this rotor ideal for i n i t i a l processing of biological ma terials to separate cell partic ulates and other large par ticles; 51,000 X g, 21,000 rpm, 940 ml in 10 tubes. TYPE 30: Provides both high centrifugal force and targe sample capacity for isolating viruses and microsomes; 105,000 X g, 30,000 rpm, 462 ml in 12 tubes.
Special-Purpose
β
Fixed-Angle
Rotors
Bucket
TYPE 40.2: S h a l l o w t u b e angle makes possible experi ments requiring minimum stirring at the end of the run, such as identifying a specific biological activity In a crude mixture; 143,000 X g, 40,000 rpm.
TYPES 30.2 and 40.3: Steep tube angle gives maximum sedimenting efficiency for separating lipoproteins and low molecular weight materials; 30.2 rotor gives 94,000 X g ; 40.3 rotor, 143,000 X g.
TYPE 40: Exerts centrifugal forces high enough to sep arate proteins and small vi ruses; 144,000 X g, 40,000 rpm, 162 ml in 12 tubes.
Swinging
Inc.
Rotors:
Ideal for zone centrifugation employing density gradients; gives complete separation of different components in a mixture. Tube is horizontal during the run and swings to vertical position on decelera t i o n . SW39L r o t o r gives 173,000 X g ; SW25.1 rotor, 90,000 X g.
Batch
Rotor:
For volumes to 1600 ml where sediment packs readily; espe cially desirable for process ing sterile materials; 35,000 W X g, 18,000 rpm.
For further information, circle number 57 A on Readers' Service Card, page 73 A V O L 3 0 , N O . I , JANUARY
1958
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57 A
