Views:6 Author:Site Editor Publish Time: 2011-04-22 Origin:Site
In addition to the effect of centrifugal separation type centrifuge, centrifugation, density gradient centrifugation medium and other factors, actual operation, the main centrifuge to determine speed and centrifugation time, centrifugal medium PH value and temperature conditions are essential .
(A) The speed centrifuge
Centrifugal acceleration depends on the rotor speed and the particle radius. Centrifugation in the conditions that are often also used to indicate the relative centrifugal force field. Practice, centrifugal force field is the average value of data. Which means the midpoint of the solution particles in the centrifugal centrifugal force field suffered.
Centrifugation centrifugation according to the different different. For differential centrifugation, it is some kind of particles to the tube end of the deposition time; on the other density gradient centrifugation, the centrifuge time is the density of particles arrive at the point of complete balance of the time; and the required density gradient centrifugation Time refers to the formation of clear boundaries of time zones. For density gradient centrifugation and density gradient centrifugation zone required for the formation of time or equilibrium time, influencing factors are complex, can be determined by tests.
Settling time of particles called to clarify the time, is the fluid particles from the centrifuge sample tube surface to the end of the deposition time required. Settling time depends on the particle settling velocity and settling distance.
(C) Temperature and PH value
In order to prevent separation of substances aggregation, denaturation and inactivation, in addition to the selection of centrifugal media attention, but also to control the temperature and PH value of solution and other media, centrifugation conditions. Centrifugation temperature control in 4 degrees, the better thermal stability for some enzymes, centrifugation can be carried out at room temperature. However, when the speed or high-speed centrifugation, high-speed rotation of the rotor heating causing the temperature rise. Therefore, the system must be frozen, to keep the temperature within a certain range.
Centrifugal media solution PH value should be stable in the PH range of enzymes, if necessary, buffer can be used. In addition, too acid or too alkaline and may cause other parts of the centrifuge rotor and corrosion, should be avoided.