I was not familiar with the terms, but in the Wikipedia article on capillary electrophoresis, "electroosmotic flow" (EOF) is associated with the motion of the ions of the buffer and "electrophoretic flow" is associated with the motion of the ions of the analyte:
"Since the electroosmotic flow of the buffer solution is generally greater than that of the electrophoretic flow of the analytes, all analytes are carried along with the buffer solution toward the cathode."
"The velocity of migration of an analyte in capillary electrophoresis will also depend upon the rate of electroosmotic flow (EOF) of the buffer solution. In a typical system, the electroosmotic flow is directed toward the negatively charged cathode so that the buffer flows through the capillary from the source vial to the destination vial. Separated by differing electrophoretic mobilities, analytes migrate toward the electrode of opposite charge.[1] As a result, negatively charged analytes are attracted to the positively charged anode, counter to the EOF, while positively charged analytes are attracted to the cathode, in agreement with the EOF as depicted in figure 3."
"The velocity (u) of an analyte in an electric field can then be defined as:
up + uo = (μp + μo)E"
where up is the electrophoretic migration velocity of an analyte toward the electrode of opposite charge and uo is the velocity of the electroosmotic flow. (See the article for definitions of the other terms.)