Why do smaller particles travel faster in gel electrophoresis?

[scilearner]

Hello guys,

 

In electrophoresis I mean sorry.

 

In electrophoresis is a similar electromotive force applied to all particles or are all particles accelerated at the same rate?

 

What I mean is let's say if every particle gets 10N.

 

F=ma and bigger particle would travel slower. So can't I include this in the answer. If they are only accelerated at the same rate I can understand how different particles would have different resistances?

 

So is the answer F=ma?

 

Thank you!!

Edited February 26, 2010 by scilearner

[CharonY]

It is slightly more complicated than that. Generally the major forces in such systems are electrophoresis and electroosmosis (the latter mostly in capillary or smaller system and assuming a homogeneous field). The electrophoretic component is determined by the electrophoretic mobility of the particle in the given system.

The force of acting on the particle scales with the charge, although geometry also has an effect (as well as media properties). Generally, however, the size effects tend to be negligible compared to the charge (on which the field really acts on).

The size dependent resolution in some standard electrophoresis techniques is based on the use of additional tricks (i.e. gels) to achieve separation in cases where the electrophoretic properties of the particles alone are insufficient or not well-defined (e.g. in case of biomolecules).