Isotachophoresis having interacting anionic and cationic shock waves

A method comprising:

• establishing anionic isotachophoresis (ITP) having one or more anionic ITP shock waves between an anionic leading electrolyte ion (LE−) and an anionic trailing electrolyte ion (TE−) in a channel;
• establishing cationic isotachophoresis having one or more cationic ITP shock waves between a cationic leading ion (LE+) and a cationic trailing ion (TE+) in the channel;
• selecting ions of the anionic ITP and the cationic ITP such that an interaction of the anionic ITP shock waves and cationic ITP shock waves modifies the effective mobility of one or more ions to provide a focusing-to-separation operation mode;
• wherein the anionic ITP shock waves and the cationic ITP shock waves propagate toward each other and interact when they meet;
• wherein one or more interaction regions are created by shock wave interaction of one or more of the anionic ITP shock waves with one or more of the cationic ITP shock waves;
• and
• analyzing at least one of the interaction regions to determine physicochemical properties of ions and/or interaction regions in the channel;
• further comprising isotachophoretic focusing of one or more analytes in a selected shock wave of the anionic and cationic ITP shock waves prior to the shock wave interaction;
• and
• further comprising electrophoretic separation of the one or more analytes in at least one of the interaction regions after the shock wave interaction, wherein shock wave interaction causes an automatic transition from an ITP focusing mode to an electrophoretic separation mode.