Electric field, separations based limitations

CE, another high performance separation technique, was also proved to be a powerful tool and an alternative for HPLC in the analysis of natural dyestuffs, even if its application in this field is still considerably limited. It could play an important role especially in the analysis of artworks, as it requires a very small volume of a sample solution (a few dozen nanolitres). In CE[ 10 14] separation of charged species is based on their different migration properties along the capillary tube which is in a constant electric field. Two platinum electrodes and both ends of a narrow bore (i.d. 25 100 pm) flexible fused silica capillary (usually 60 100 cm long) filled with a suitable conducting buffer are immersed in two... 

The feasibility of the approach has been demonstrated with base-line resolved separations of tagged amino acids at a electric field strength of 50 V/cm applied across the separation length (bed width) of 1 cm [81]. However, it is clear that high resolution separations will not be the domain of this technique, for the absolute magnitude of the separation voltage across the separation bed is limited to -100-200 V (see Eq. 8). The flow through the outlet channels was combined into one hole in the cover plate, therefore fraction collection experiments were not possible in this study. 

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