Patent ID: 7390389

Claim:
An apparatus for electrophoretic separation and purification of at least one charged and/or neutral analyte from a solution by isoelectric focusing, said apparatus comprising: a series of at least two compartments having at least one wall portion composed of a chemical buffering means forming a non-convective liquid junction interconnecting said at least two compartments, and said chemical buffering means defining in each compartment of the series one of a fixed pH value or a pH gradient in its portion contacting said solution; a thin layer fluidic connection between said at least two compartments allowing non-convective passage of solution from one compartment to another, said thin layer fluidic connection being one of a hole, a micro-channel, an array of holes or micro-channels, and a hollow passage; and said thin layer fluidic connection being characterised by a lower resistivity than that of said chemical buffering means, thereby providing a liquid junction interconnecting said at least two compartments having a higher conductivity than that provided by said chemical buffering means; and electrodes placed in at least two of said compartments at extremities of the series for forcing said charged analyte and/or undesired charged compounds present in said solution to move from one of said compartments to another or to the other of said compartments by virtue of the charge of said analyte and/or said undesired charged compounds at the pH value or in the pH range defined by the portion of the chemical buffering means contacting said analyte solution in each individual compartment of the series.