A new device for measuring distribution of electric fields in isothermic gel electrophoresis

Electrophoretic potentials inside a polyacrylamide slab gel were measured by a platinum electrode probe holder. These electrodes were inserted into the gel and the distribution in space of electric fields was explored by a multiplexing procedure. Horizontal and vertical arrays of electrodes enabled the evolution of average fields and local potential gradients to be monitored during electrophoretic migration. The results show the nonhomogeneity of mean field strength measurement along a slab gel, the dependence of the potential distribution according to the chemical composition of buffers, moving boundary detection and the resulting potential gradient variation resulting from conductance variation on either side of the boundaries. The role played by the gel and the electrode geometry in the map of potential distribution is underlined.