logging in or signing up Capillary Electrophoresis aSGuest72851 Download Post to : URL : Related Presentations : Let's Connect Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 695 Category: Science & Tech.. License: All Rights Reserved Like it (1) Dislike it (0) Added: October 26, 2010 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: wendelfba (37 month(s) ago) Very nice presentation, congratulations. Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Capillary Electrophoresis : Capillary Electrophoresis Electrophoresis—An Overview : Electrophoresis—An Overview Definition: The differential movement for migration of ions by attraction or repulsion in an electric field. Separation of components of a mixture using an electric field v=Eq/f v = velocity of molecule E = electric field q = net charge of molecule f = friction coefficient Electrophoresis- overview cont. : Electrophoresis- overview cont. Can determine the size, shape, and charge of a molecule Different forms of electrophoresis are used for each of these factors independently or in combination. Types of Electrophoresis : Types of Electrophoresis Capillary Native Polyacrylimide Gel Electrophoresis (PAGE) SDS-PAGE Slab Paper Capillary Electrophoresis Apparatus : Capillary Electrophoresis Apparatus Capillary Electrophoresis – The Basics : Capillary Electrophoresis – The Basics Electrophoresis in a buffer filled, narrow-bore capillaries Each capillary is about 25-100 μm in internal diameter When a voltage is applied to the solution, the molecules move through the solution towards the electrode of opposite charge Depending on the charge, the molecules move through at different speeds Separation is achieved Basics cont. : Basics cont. A photocathode is then used to measure the absorbencies of the molecules as they pass through the solution The absorbencies are analyzed by a computer and they are represented graphically Electrophoretic Mobility : Electrophoretic Mobility The movement of ions solely due to the electric field, potential difference Cations migrate toward cathode Anions migrate toward anode Neutral molecules do not favor either Electrophoretic Mobility : Electrophoretic Mobility v=Eq/f vep = μepE μ = q/(6πηr) η is buffer viscosity r is solute radius Properties that effect mobility Voltage applied Size and charge of the solute Viscosity of the buffer Electroosmotic Flow : Electroosmotic Flow As the buffer sweeps toward the anode due to the electric field, osmotic flow dictates the direction and magnitude of solute ion flow within the buffer All ions are then swept toward the anode. Negative ions will lead the neutral ions toward the anode Positive ions will trail the neutral ions as the cathode pulls them Electroosmotic Mobility : Electroosmotic Mobility veof = μeofE μeof = ɛζ / (4πη) ɛ = buffer dielectric constant ζ = zeta potential Zeta Potential The change in potential across a double layer Proportional to the charge on the capillary walls and to the thickness of the double layer. Both pH and ion strength affect the mobility Total Mobility : Total Mobility vtot = vep + veof Migration times vtot = l/t l = distance between injection and detection t = migration time to travel distance l t = lL/((μep + μeof)V L = length of capillary V = voltage Slide 14: Ooooo! It MOVES Equipment : Equipment Capillary tube Varied length but normally 25-50 cm Small bore and thickness of the silica play a role Using a smaller internal diameter and thicker walls help prevent Joule Heating, heating due to voltage Equipment : Equipment Because ions are in the bulk solution are about to travel through the capillary without interference from the capillary itself, there is no dramatic drop in potential within the capillary No meniscus is made Equipment : Equipment Detector UV/Visible absorption Fluorescence Radiometric (for radioactive substances) Mass Spec. Yowzah!!! Applications : Applications Analysis of carbohydrates Analysis of inorganic anions/metal ions DNA profiling Protein identification Advantages Fast Small Sample Relatively inexpensive Automated Disadvantages Cannot identify neutral species Joule Heating Cannot discern shape You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.