Centrifuging: Short time/high speed vs. Long time/low speed

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DatUVa
DatUVa's picture
Centrifuging: Short time/high speed vs. Long time/low speed

Is it generally effective to substitute a long duration, low-speed centrifugation in place of a shorter duration, higher speed centrifugation? I have found this to be okay in some applications, but was wondering what other peoples' thoughts/experiences were, particularly regarding extremely high speed centrifugations.

Sangram
Sangram's picture
It depends upon the

It depends upon the application ........,you can not some times increase the "g" .

Omai
Omai's picture
I believe it depends on what

I believe it depends on what you are trying to pellet (or separate). Some things (organelles, proteins, membranes etc) require a minimum speed to pellet. Too low, and they won't spin down. Too high, and you may destroy what you are looking for. If your are within a certain range, I don't see why a slightly higher, but shorter time frame would have ill effects. This probably should be worked out empirically on a case by case basis.

Omai

mchinmoyee
mchinmoyee's picture
Depends on the purpose , size

Depends on the purpose , size & density of the biomolecule, and also the medium in which the separation is done.

For a typical cell homogenate, a 10 min spin at low speed (400-500 x g) yields a pellet consisting of unbroken tissue, whole cells, cell nuclei, and large debris.
The low speed pellet is traditionally called the nuclear pellet. A 10 min spin at a moderately fast speed, yielding forces of 10,000 to 20,000 x g brings down mitochondria along with lysosomes and peroxisomes. Therefore the second pellet in the traditional cell fractionation scheme is called the mitochondrial pellet.
A one hour high speed ultracentrifuge run that generates a force on the order of 80,000 x g yields a microsomal pellet.
Spin for several hours at 150,000 x g or so, and you can bring down ribosomes and even the largest of macromolecules.

below link will be useful,
http://homepage.usask.ca/~paa151/centrifugation.htm