CAPILLARY ZONE ELECTROPHORESIS AND ISOTACHOPHORESIS - A COMPARISON BY INFORMATION-THEORY

A comparison of the potentialities of free capillary zone electrophoresis and isotachophoresis with respect to qualitative analysis i.e. as a means of identification, is given based on information theory for the one dimensional case, i.e. single electrolyte systems. The maximum number of peaks which can be differentiated in a zone electropherogram, in the absence of electroosmosis, is derived. This number depends on the ratio of the migration times, or the mobility range, of the fastest and the slowest migrating separands, on the desired resolution and on the number of theoretical plates. Based on this peak capacity, the maximum information content I(max) (decision content) is calculated and both electrophoretic techniques are compared by means of this rational parameter. Within certain limitations it is found that the decision content of free capillary zone electrophoresis is about 7.7 bit, which is about 1 bit greater than the corresponding value for isotachophoresis (6.7 bit).