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 is sufficient to calculate either one of the potentials. Therefore, standard electrode potential is commonly written as standard reduction potential. The electrode potential cannot be obtained empirically. The galvanic cell potential results from a "pair" of electrodes. Thus, only one empirical value is available in a pair of electrodes and it is not possible to determine the value for each electrode in the pair using the empirically obtained galvanic cell potential. A reference electrode, standard hydrogen electrode (SHE), for which the potential is "defined" or agreed upon by convention, needed to be established. In this case SHE is set to