Electroosmotic flow velocity magnitude

Electroosmotic flow velocity, Veof, is a function of the magnitude of the applied electric field and the buffer solution s electroosmotic mobility, )J,eof. 

Figure 33-9 Velocities in the presence of electroosmotic flow. The length of the arrow next to an ion indicates the magnitude of its velocity the direction of the arrow indicates the direction of motion. The negative electrode would be to the right and the positive electrode to the left of this section of solution.

Electroosmotic velocities of buffered solutions are shown for a bare silica capillaiy and one with aminopropyl groups (silica—Si—CHiCHiCHjNlL) covalently attached to the wall. A positive sign means that flow is toward the cathode. Explain the signs and relative magnitudes of the velocities. 

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