Polyacrylamide gel electrophoresis the top to create the sample wells. After the gel is polymerized the comb can be removed and the gel is ready for electrophoresis. Various buffer systems are used in PAGE depending on the nature of the sample and the experimental objective. The buffers used at the anode and cathode may be the same or different. An electric field is applied across the gel, causing the negatively charged proteins or nucleic acids to migrate across the gel away from the negative electrode (which is the cathode being that this is an electrolytic rather than galvanic cell) and towards the positive
Standard electrode potential potentials are independent of the number of electrons transferred —they are expressed in volts, which measure energy per electron transferred—and so the two electrode potentials can be simply combined to give the overall "cell" potential even if different numbers of electrons are involved in the two electrode reactions. For practical measurements, the electrode in question is connected to the positive terminal of the electrometer, while SHE is connected to the negative terminal. The larger the value of the standard reduction potentials, the easier it is for the element to be reduced (accept electrons); in other words, they are better oxidizing