What term refers to the movement of buffer ions and solvent relative to a fixed support in electrophoresis?

What term refers to the movement of buffer ions and solvent relative to a fixed support in electrophoresis?

• A. Electroendosmosis
• B. Isoelectric focusing
• C. Iontophoresis
• D. Zone electrophoresis

Answer: (A)

The movement of buffer ions and solvent relative to a fixed support in electrophoresis is called electroendosmosis. This bulk flow occurs because the solid surface (such as the gel or paper) carries charge at the interface with the buffer, creating an electrical double layer. When an electric field is applied, the counterions in that layer drag the adjacent liquid along, producing a net flow of the buffer and solvent toward a particular electrode. This solvent movement can influence how analytes migrate, sometimes aiding or opposing their travel depending on the system. The other terms describe different phenomena: isoelectric focusing relies on a pH gradient to separate proteins by their isoelectric points; iontophoresis involves moving charged substances into tissues with an electric current; zone electrophoresis is a general approach to forming separated zones of analytes during electrophoresis, not specifically describing the bulk solvent flow.

The movement of buffer ions and solvent relative to a fixed support in electrophoresis is called electroendosmosis. This bulk flow occurs because the solid surface (such as the gel or paper) carries charge at the interface with the buffer, creating an electrical double layer. When an electric field is applied, the counterions in that layer drag the adjacent liquid along, producing a net flow of the buffer and solvent toward a particular electrode. This solvent movement can influence how analytes migrate, sometimes aiding or opposing their travel depending on the system.

The other terms describe different phenomena: isoelectric focusing relies on a pH gradient to separate proteins by their isoelectric points; iontophoresis involves moving charged substances into tissues with an electric current; zone electrophoresis is a general approach to forming separated zones of analytes during electrophoresis, not specifically describing the bulk solvent flow.