Isotachophoresis

The isotachophoresis (ITP) is an analytical method which is used for example in the testing of water samples.

The ions to be examined are separated in the electrolyte solution in an electric field. This happens due to different ion mobilities. By using a discontinuous buffer system with a common counterion, the different ions move at the same speed after separation. Hence the name of iso (ἴσος) = equal and tachos (τὸ τάχος) = speed.

An electrolyte is used that has a high ion mobility and thus moves quickly in the field. This is located in front of the sample in the separating capillary and is therefore called the leading electrolyte. An electrolyte that has a low ion mobility and thus moves slowly in the field is located behind the sample in the separation capillary and is therefore called terminating electrolyte. Since the field between these two electrolytes has special properties, all ions in between are given a specific sequence and concentration. These are independent of the initial state.

The procedure is similar to chromatography .

The use of a collecting gel in SDS gel electrophoresis of proteins is also based on isotachophoresis.

literature

• Manfred Gey: Instrumental Analysis and Bioanalytics: Biosubstances, Separation Methods, Structural Analysis, Applications . 3. Edition. Springer Spectrum, Berlin, Heidelberg 2015, ISBN 978-3-662-46254-6 , pp. 219-220 .