centrif. force: g or rpm?

Denni Schnapp ds4 at st-andrews.ac.uk
Fri Feb 16 05:50:08 EST 1996

Ha! I have been waiting for this thread for a long time. It is true
that the least ambiguous way to report centrifugal force is the 
rotor type and rpm, because conversion tables exist for all rotor
types or g can be figured from rotor dimension. However, most 
people will write things like " the sample was centrifuged for 1 h
at 26 000 rpm" and not specify the rotor type and this really
makes this information meaningless!! It can also be difficult to
obtain the info about rotor dimensions. I therefore favour ex-
pressing centrifugal force in its proper unit, g, and this usually
refers to g in the middle of the tube, I thought. For most appli-
cations, with virus purification at least, I don't think the exact
g-force is important, generally the higher the better within the
range specified in method guidelines such as found in Maniatis or
other lab manuals. I will follow this debate with interest...


Denni (ds4 at st-and.ac.uk)

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