CHEM 2331 Study Guide - Midterm Guide: Electrophoresis, Polyacrylamide Gel Electrophoresis, Joule Heating
31 Mar 2016
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Document Summary
Separation of molecules based on electrophoretic mobility. Sec = separation based on size and shape but electrophoresis is like that but also with separation by charge. Equations: fe = electric force ion experiences that counteracts frictional force, ff = frictional force, u = electrophoretic mobility. Steps: a charge is placed in an electric field & experiences a force, ions move & experience frictional force, equilibrium is reached between two forces in constant electric field, electric field = e. Electrophoretic mobility of molecule does not depend on e field strength. Joule heating: bad, as e increases, so does joule heating, leads to convection currents, higher diffusion, zone distortion (band broadening), thermal degradation, and lower viscosity, to lower joule heating. Use lower electric field strength or lower conductivity -> allows for slow separation. Smaller diameter or gels -> help dissipate heat. Refrigeration -> in cold room, cooling plates, etc. Two types of electrophoresis: gel electrophoresis.
