Preparative Capillary Isotachophoresis

 

Capillary isotachophoresis can be used with slight modification to the basic analytical isotachophoreis instrument for small scale preparative separations (ng to mg range of samples). A diagram of an analytical instrument and one modified for preparative purposes is shown in figure 22.

 

 

Figure 22. An Analytical Isotachophoresis and a Modified Form for Small Scale Preparative Separations

 

The basic difference in the preparative device involves the insertion of two T-pieces between the detector and the leading electrolyte reservoir. One T-piece must be situated close to the detector and allows a sample component migrating through the detector to be diverted to a fraction collector. The second T-piece can be some way away from the detector and provides a flow of electrolyte that, when activated, can drive the sample leaving the detector into the fraction collector as opposed to continuing along the capillary.