Main Differences Between Electrophoresis and Electroosmosis 10

First, the nature is different.

1. Electroosmosis: In the electric field, the solution is relatively charged due to the adsorption of positive and negative ions in the water by the porous support. Under the action of an electric field, the solution moves in a certain direction.

2. Electrophoresis: Under the action of the electric field, the charged particles move towards the electrode opposite to their electrical properties.

Second, the phenomenon is different.

1. Electroosmosis phenomenon: the electroosmosis velocity of the liquid is simply proportional to the potential between the solid and liquid phases, so the electroosmosis can be used to measure the potential, but this method is only limited to materials that can form capillaries or porous media.

2. Electrophoresis phenomenon: under certain conditions, the movement distance (mobility) of charged particles per unit time is constant under the action of unit electric field intensity, that is, the physicochemical characteristic constant of charged particles. Different charged particles have different charges or charge-to-mass ratios, although they have the same charge.

After electrophoresis in the same electric field for some time, they separate from each other due to the difference in distance traveled. The separation distance is proportional to the applied electric field voltage and the electrophoresis time.

Third, the application is different.

1. Electroosmosis application: It is often used in industry to enhance the fluid mixing in the microfluidic channel, remove the moisture in the product, prepare porous dielectric materials, control the movement of liquid films in biochips and other practical applications.

2. Electrophoresis application: It has been widely used in analytical chemistry, biochemistry, clinical chemistry, toxicology, pharmacology, immunology, microbiology, food chemistry and other fields.

Electroosmosis: one of the electrokinetic phenomena. Refers to the relative motion of a liquid (usually water) relative to a fixed solid phase in contact with it under the action of an electric field.

Electrophoresis: Charged particles move towards the electrode opposite to their electrical properties under the action of an electric field, which is called electrophoresis.

Electrophoresis is similar to electromigration. However, electrophoresis is generally large particles. Whereas, electromigration is ionic.

Electrophoresis: the movement of the dispersed phase, and the dispersed medium is relatively fixed;

Electroosmosis: The movement of a dispersed medium, and the dispersed phase is relatively fixed.

Electrophoresis is the directional migration of sol particles with a tumbling cherry charge under the action of an external electric field. Large-plex electroosmosis is the movement of the dispersed medium through the porous material under an applied electric field, that is, the solid phase does not move while the liquid phase moves. When the liquid passes through the capillary or porous plug in the capillary under the action of external force, the potential difference caused by the flow of the liquid medium relative to the stationary charged surface is called the flow potential, which is a concomitant phenomenon of electroosmosis; Under the action of external force, the dispersed phase particles settle rapidly in the dispersed medium, and the electric potential difference will be generated between the surface layer and the inner layer of the liquid medium, which is called the sedimentation potential, which is a concomitant phenomenon of electrophoresis.

Heng Min of electric double layer theory believes that when the solid is in contact with the liquid, due to the selective adsorption of the solid to the liquid or the separation of solid molecules, the two phases of the solid and liquid have different charges, and the electric double layer is formed at the interface. The electric double layer is divided into a compact layer and a diffusion layer, and the potential difference between the shear surface and the liquid body between the two layers is called the electric potential.

In the case of colloidal particles - their surface is made up of compact and diffuse layers. The electric potential is the potential difference between the colloidal particles and the ions in the diffusion layer. In the applied electric field acts f. The relative movement of the colloids with oppositely charged ions in the diffusion layer leads to the generation of electrophoresis.

The porous membrane used in electroosmosis is a collection of several capillaries, and the walls and liquids in each capillary tube form an electric double-layer structure. When an electric field is applied, the solid and its surface solvated layer (compact layer) do not move. In the diffusion layer, the oppositely charged ions on the surface of the solid move and because these ions are solvated, the movement of the dispersed macro companion medium can be observed.

The liquid that moves as a whole in the phenomenon of electroosmosis is called electroosmotic flow. Quartz is usually used as a capillary material in HPCE, and the isoelectric point of quartz is about, because of this in the commonly used buffer solution (pH 3), the tube wall is negatively charged, and the silicon hydroxyl group (Sioh) on the surface of the quartz capillary is ionized into siloxy anion (SiO-), and the hydrated ions (generally cations) in the solution are adsorbed near the surface of the capillary to form an electric double layer. When voltage is applied at both ends of the capillary, the cation ballast in the electric double layer moves towards the cathode, and because the ions are solvated, the overall solution in the capillary moves towards the cathode, forming an electroosmotic flow (EOF).

Electroosmotic flow is of great significance in the process of electrophoresis separation. It is embodied in: the positive and negative separation of the coarse and neutral molecules in the mixture can be separated by differential migration; By controlling the size and direction of the EOF, the separation efficiency, selectivity, and resolution of CE can be improved.

The colloidal particles have a large diameter and cannot be rounded through the semi-permeable membrane, and the solute particles in the solution can collapse through the semi-permeable membrane, which can prove that the colloidal particles are larger than the electrolytic particles in the solution

Therefore, C