Frans_M_Everaerts_Isotachophoresis_378342.pdf

Fig.4.6. Simplified model for the formation of the zonesin an isotdchophoretic separation of a five-component sample (A, -As). The sample is introduced
already sandwiched between the leading and terminating electrolytes. At various times, mixed zones disappear, as a function of the effective mobilities of
the ionic species and their actual concentrations. Such a figure can only be realized in practice if a fast scanning device is available. At the time r=8 (x),
the steady state has been reached and the sample zones will not broaden further, assuming that the electrolyte is of constant composition and the cross-
section of the separation chambe1 is constant. The zone lengths are also not influenced by variations in the electric current, assuming that the pK values of
the ionic species present are not influenced by the temperature. In this sample, the ‘dilution’ effect of isotachophoresisis shown. If one compares this figure
with Fig.2.7, it should be noted that the situationgiven in the present figure can be obtained only if a counter flow of electrolyte is present, because for a
complete adaptation of all concentratidns the terminator ion must have passed the position where the sample is introduced, although we recommend
to start the counter flow of electrolyte as soon as the terminating zone has passed the injection point.