For example I am using this protocol for separation in centrifuge: 10000g for 10 min . I want to decrease the time of centrifuge to 5 min, how can I increase the speed of centrifuge? Is the a formula to use it?
If you know the rotor used in the original method, this is quite easy using the pelleting efficiencies k of the two rotors: k1/t1 = k2/t2. You can get k from the rotor handbook, but it can also be calculated: k = t/S = ln(rmax/rmin) * 253303 / sqrt(rpm/1000). This formula is also useful if a rotor is old and can be used only at reduced rpm. In your case, as the desired time t2 is known, you'd have to calculate the minimal k2 and then select the rotor accordingly.
I have covered the theory of cantrifugation in doi:10.1007/978-1-4419-7251-4_25.
If you are using the same rotor and centrifuge device in which your k-factor is constant, then I guess you can use this relative to calculate new rpm: t1(V1)^2 = t2(V2)^2
The abovementioned relative can be calculated from these equations:
K=(2. 533 x 10^11) ln (rmax/rmin)/n^2
,
t1= t2 (k1/k2)
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