The Beckman Coulter Optima TLX Ultracentrifuge is a tabletop ultracentrifuge that can be used for many types of high-speed applications. It is a vital instrument in our lab that is used on a daily basis. This ultracentrifuge can accommodate any Beckman Coulter TL-series rotors – there are a number of different models of these designed to be used with common tube sizes. Some of the features of the Optima TLX has include an easy to use control panel, a temperature control system, a self-purging vacuum system, a programmable memory that can store up to 10 different profiles and a versatile acceleration/deceleration program. In addition, because this instrument has a maximum speed of 120,000 rpm, it comes with many safety features.
The control panel for the Optima TLX is conveniently located on top of the machine to allow easy access and visibility. Run parameters are entered by keys on the control panel and there is a positive “beep” noise to verify the values entered. During the run, the control panel shows the actual conditions, such as speed, temperature, and time. Pressing any one of the ‘speed’, ‘temperature’, or ‘time’ buttons will show the set values that were initially programmed.
The thermoelectric temperature control system utilizes forced air and does not require any coolant. Once the door to the rotor chamber is closed, the temperature control system is activated automatically. The run temperature can be set between 0 C and 40 C. There is a sensor in the chamber that continuously measures the temperature of the chamber. And, there is a microprocessor in the chamber that calculates the chamber temperature to keep the rotor at the selected temperature.
The self-purging vacuum system consists of a series of mechanical vacuum pump with a diffusion pump, which allows the chamber pressure to reach below 10 microns (1.3 Pa). When the door is closed, the vacuum system is automatically turned on. This system continuously removes moisture from the chamber. Once the VAC message on the control panel disappears, the centrifugation begins. If there is a loss of vacuum such that the vacuum is above 500 microns, the instrument is decelerated to 5000 rpm. If the vacuum still remains above 500 microns, the instrument will come to a stop.
In addition to allowing one to set up parameters (speed, time, temperature, acceleration/deceleration) manually, one can also duplicate runs quickly by choosing a pre-programmed parameter, which can contain up to 5 steps. This instrument allows one to select 10 different acceleration rates (the time it takes to reach 5000 rpm from 0 rpm) to protect specific gradient and sample-to-gradient interfaces, i.e. sucrose gradients. If no selection is made or the display is left blank, the instrument accelerates at the maximum rate. Also, eleven deceleration rates (the time it takes to decelerate from 5000 rpm to 0 rpm) can be selected to allow for maximum separation. Again, if no selection is made or the display is left blank, the instrument decelerates at the maximum rate. A run can be stopped at any time by simply pressing the ‘stop’ button.
Some of the safety features include a steel chamber door, which has an electromechanical door-locking mechanism. The door automatically locks when the door is manually closed. The door can only be opened when the rotor comes to complete rest. There is also an imbalance detector, which stops the run if the loaded rotor is not balanced within a certain range. There is also an over speed identification system, which stops the run if the set speed is greater than the maximum speed permitted by that type of rotor.
Surprisingly, an instrument of this size makes very little noise and does not produce much noticeable heat. We have had this instrument for about six months and we use it on a daily basis. So far we have not had any problems with it. Therefore we have no problems recommending this instrument for any lab that requires a tabletop ultracentrifuge for high-speed applications.
Hee Chul Lee
Graduate Student
Dept. of Biochemistry
NYU School of Medicine