AU Biomaterials Design Lab:Equipment/Centrifuge

Description

Thermo Scientific RC-6+ Centrifuge: two different rotars are available with this model.

• Sorvall SH-3000 Swinging Bucket Rotor
• Sorvall F21S-8x50y rotor
  • This instrumentation is used to rotate an object at varying speeds in order to separate out different substances based on their different densities at controlled temperatures. More dense substances are pushed to the bottom while less dense substances are able to move to the top. Between the two rotors, the rpm ranges from 300-22000rpm.

Purpose of Use

• Using different rotors allows for a variety of speeds to be used in the centrifuge, depending on the substances that you are trying to separate out, different speeds and different lengths of time may be necessary.
• It is first important to note that the rotar is securely attached in the rotor chamber.
• For the Sh-3000 rotor, the rotor body had four aluminum buckets which hang from the rotor body on support pins.the buckets accept a variety of adapters: glass and plastic tubes or bottles up to 98mm in diameter.
• Because the instrument is spinning at high speeds, it is extremely important to balance out the system. When using the rotor buckets or microplate carriers, in the Sh-3000 rotor, the opposing buckets or micro plate carriers need to be balanced to within 10 grams. For the 6 plus super speed centrifuge, the balance needs to be within .01grams of each other.

Basic Operation

1. Turn the machine on
2. Open the chamber door and install the rotor, if needed, make sure that the rotor cover is installed and place the rotor on the drive spindle and lock it in place turing the rotor locking knob counterclockwise
3. close the chamber door
4. Set the run screen with the appropriate parameters ( including specifications for temperature, time, and rounds per minute (rpm). Be sure to monitor the centrifuge in the beginning to ensure that no unbalance has been detected.
5. The centrifuge works by spinning the contents of the rotor both horizontally and vertically.

This Centrifuge can be used to separate out solutions and substances based on their individual densities. More dense substances get pushed down while less dense substances are brought to the top.

Location

• Beeghly 314
• American University
• Washington, DC
  • access to the room is restricted; see Dr. Miller, Dr. Hartings or Dr. Fox for access.

Contact

• contact with questions or to schedule access via email
  • Dr. Matt Hartings
  • Dr. Abigail Miller

Use

[Centrfuge Manual]

• Key terms to know

Relative centrifugal force refers to the force during centrifugation that moves the particulate outward from the center of rotation. force is proportional to the radial distance and the square of the rotor speed. K factor= the clearing factor for the rotor. Critical speed= speed at which any rotor imbalance will produce a driving frequency equal to the resonant frequency of the rotating system. At thsi speed, the rotor may produce large amplitude vibrations which can be felt int he instrument frame.

Safety

• Be wary of contamination and possible leakage when working with radioactive, toxic, or pathogenic materials.
• Be sure to securely lock the rotor to drive before starting a centrifuge run
• Do not expose aluminum rotor components to strong acids, bases, or alkaline laboratory detergents. The bearings of the drive unit may corrode or deteriorate.
• Do not operate centrifuge with a rotor out of balance or at the critical speed as this will damage the centrifuge and reduce the component life.
• Make sure centrifuge is grounded properly to avoid electrical shock hazards.
• DO not centrifuge materials in this instrument capable of developing flammable or explosive vapors or extreme exothermic reactions.
• Maintain a clearance around the centrifuge of 30cm or more in all directions.

Specifications

• THE RC 6-PLUS

-Process 4 liters of sample in a single run -9 acceleration and 10 deceleration settings - wide range of rotors are applicable to this centrifuge -Speed selection range= 300-22000rpm +/- 25 rpm -max RCF= 52200 x g -Temp selection range and accuracy= -20°C to 40°C +/- 2°C -Run time selection range= 1 minute- 99 hours and 59 minutes -ambient temp range= 2°C to 40°C -mass (weight)= 350 kg -max capacity= 4000mL

• For SH-3000 rotor (w/ buckets)

-The Design Mass for each rotor compartment is 1805 grams at 4700 rpm. -Diameter= 37.1 cm -Mass= 6000 grams -number of places=4 - Max Rotor speed= 4700 rpm -relative centrigual force (RCF) at max speed= 4575 -K Factor at Max Speed= 8138 Max Compartment mass= 1805 grams Critical Speed= 900rpm

• For SH-3000 (w/microplates)

-Diameter= 35.9cm -mass= 5275 grams -number of places=4 -max rotor speed= 4700 -RCP at max speed= 3706 -K factor at max speed=5024 -Max compartment mass= 987g -Critical speed= 900 rpm

In swinging bucket rotors, the swings clearance of the bucket and contents as they swing from the vertical to horizontal position during centrifugation. proper clearance must be allowed to prevent the tubes from hitting the rotor body and breaking.

• For the F21S-8x50y rotor

-code =41 -max speed= 20000 rpm -max RCF= 47.488 -K factor= 739 -Max compartment mass= 115grams -max radius= 10.6 cm -min.radius= 3.3cm

References

• [Thermo-scientific centrifuge]