The Sorvall Evolution Centrifuge is a robust, aesthetically pleasing instrument for any biological laboratory. With a nice sliding door, in contrast to the flap-like door for most other models, this instrument offers several attractive features over many of its competitors. The machine can use several rotors with different bucket sizes but in our lab, we only use three of the rotors for most routine centrifugation purposes. The largest of them is the SLC4000 that can accommodate four 1 liter bottles. This is extremely useful for harvesting large culture volumes for protein preparation. The rotor is surprisingly light, can be easily handled and can reach a maximum of 9000 rpm (15,000 g). Another rotor, the SLC6000, is also available that can accommodate six 1 liter bottles. The GSA rotor is most commonly used in our lab and can accommodate six 250 ml bottles (maximum speed of 27,000 g). The smallest of the three rotors we use is the SS34, which can hold eight 50 ml tubes (maximum speed of 50,000 g). This rotor is extremely useful for DNA and protein preparations. All the rotor models and corresponding speed limits are pre-stored in the memory.
The acceleration/deceleration rates are very fast for this instrument, with three settings available (we prefer to use the maximum for all rotors). The cooling rate of the instrument is very fast, thus saving time. However, we still prefer to cool the rotor prior to the start of a run.
The machine has a large display unit and can store a maximum of five recent runs. The rotor number, speed, time and temperature have to be set but can be changed in the middle of a run. This ability to accelerate to higher speeds after a given period of time is extremely handy when one wants to check for perfect balancing of the samples. We usually run the machine at a lower speed to check for smooth performance and balancing before setting it to the desired higher speed when using the SS34 rotor.
Condensation of water in the centrifuge chamber is a common problem in refrigerated machines running at low temperatures. One interesting feature in this machine is a unique mechanism to avoid this problem. The inner side of the chamber is flushed with warm air so that the chamber surface reaches room temperature quickly, preventing water condensation.
On the downside, it must be mentioned that the instrument does have a large footprint in the lab. Given the useful qualities this should not be of major concern, especially in a central facility.
Vikas Jain
Research Scholar
Indian Institute of Science
India